Nuclear Physics Seminars

Whether neutrinos are Majorana or Dirac particles is an open question. Theoretically, it is also possible that neutrinos are pseudo-Dirac, which are fundamentally Majorana fermions, but essentially act like Dirac fermions in most experimental settings, due to extremely small active-sterile mass splitting. Such small values of mass splitting can only be accessed via active-sterile oscillations over an astrophysical baseline, or via decays of neutrinos over a cosmological time scale. In this talk, I will use the multi-messenger observation of high-energy neutrino sources and the excess radio background detection to probe two different regimes of pseudo-Dirac neutrino parameter space. 

"For a long time, it was believed that the fundamental constituents of atoms were electrons and nucleons until experiments conducted in the late 1960s at Standford Linear Accelerator Center (SLAC) proved the existence of internal degrees of freedom in the nucleons. These ones are called quarks and gluons, or collectively partons. With QCD as the fundamental theory for strong interactions, we can describe hadronic structure via correlators of partons giving rise to the so-called parton distribution functions (PDFs) and generalized parton distributions (GPDs) when the so-called collinear factorization applies. The non-elementary nature of hadrons makes these correlators perturbatively unsolvable so we can only measure or model them. 

 

This seminar will cover the discovery of the proton as a composite object through deep inelastic scattering (DIS), from both the experimental and theoretical sides. Modern experiments/theory on other processes such as deeply virtual, timelike and double deeply virtual Compton scattering (DVCS, TCS and DDVCS) will be covered too, giving a broad picture on the current access to parton distributions."

This talk presents an exploration of meson structure studies using the Sullivan process, which provides valuable insights into the fundamental nature of hadrons within the framework of Quantum ChromoDynamics (QCD).  The primary focus is on pion and kaon structures, offering unique opportunities for enhancing understanding of the emergent hadron mass-generating mechanism (EHM) and Generalized Parton Distributions (GPDs).

The KaonLT experiment, conducted in Hall C at Jefferson Lab (Jlab), employs a methodology comprising detector calibrations, efficiency studies, and offsets optimizations. These steps lead to the extraction of the kaon electroproduction cross section and the crucial separation of longitudinal and transverse components which, when warranted by the data, allow for kaon form factor extraction.

In addition to the Jlab efforts, ongoing research includes GEANT4 detector simulations to investigate the necessary requirements for measuring pion and kaon structure functions at the forthcoming Electron-Ion Collider (EIC). These investigations contribute significantly to constraining meson Parton Distribution Functions (PDFs) and validating the behavior of valence quark, sea quark, and gluon distributions.

Lymphocytes are a key component of the adaptive immune system. The presence of high numbers of lymphocytes, especially T cells, has been reported to be an indicator of good prognosis in many types of cancer. However, lymphocytes are highly radiosensitive and Radiation-Induced Immune Suppression (RIIS) means destroying existing as well as newly created lymphocytes. In the era of immunotherapy, predicting time-dependent immune levels could allow optimum time for immunotherapy administration. In this talk, I will present a comprehensive model to predict time-dependent absolute lymphocyte count (ALC) in blood for early-stage lung cancer patients following Stereotactic Body Radiation Therapy (SBRT) treatment. This complex model includes blood circulation among blood-rich organs such as heart, aorta, vena cava, pulmonary artery, etc; intertwined with lymphatic circulation among lymph-rich organs such as spleen, bone marrow, lymph nodes, liver, lung, etc. The model was trained on a set of retrospective lung SBRT patients and tested on a set of ongoing clinical trial patients. The model shows good accuracy in both training and testing datasets, with room for improvement.

In 1983, results published by the European Muon Collaboration (EMC) at CERN suggested that the quark structure of nucleons are modified when they are bound together in the nuclear environment. This modification, now called the EMC Effect, was largely unexpected and has been the subject of a significant amount of theoretical and experimental effort over the past 40 years to determine its underlying cause. Despite this effort, the exact mechanism that causes the EMC Effect has continued to elude physicists.

Experiment E12-10-008 at Jefferson Lab aims to shine a bright new light on this 40-year-old problem. Having collected data from September 2022 through February 2023, this experiment utilized the high luminosity 12 GeV electron beam of CEBAF to probe, with high precision, the quark structure of nearly 20 different nuclei. Data from this experiment will provide a significant contribution to the global set of EMC Effect data, producing the first measurements of the EMC Effect in many new nuclei and reducing uncertainty on previously studied nuclei. In this seminar, an overview of the EMC Effect will be given and the physics motivation of experiment E12-10-008 will be presented.

The constituents of dark matter are still unknown, and the viable possibilities span a very large mass range. Specific scenarios for a thermal origin of dark matter sharpen this mass range to within about an MeV to 100 TeV. Most of the stable constituents of known matter have masses in the MeV to GeV range, and a thermal origin for dark matter works in a simple and predictive manner in this mass range as well, yet it remains largely unexplored. The Heavy Photon Search (HPS) at Jefferson Lab is a fixed target experiment that uses an electron beam to probe models of thermal dark matter involving sub-GeV dark photons. HPS searches for visibly decaying dark photons through two distinct methods - a resonance search in the e+e- invariant mass distribution and a displaced vertex search for long-lived dark photons. This seminar will give an overview of the theoretical motivations, the main experimental challenges and how they are addressed, the results for the 2016 Engineering Run, and future data and upgrades. In addition, an introduction to the Light Dark Matter eXperiment (LDMX), a planned next generation experiment at SLAC that will search for invisibly decaying dark photons through a missing-momentum experiment, will be presented.

Understanding the structure of hadrons from first principles has been a long standing issue. Within the last decade, lattice QCD calculations have begun to probe the partonic structure of pions and nucleons. The "pseudo-PDF" approach has been successful in calculating the parton distribution functions of nucleons and pions and calculations with control of the systematic errors are underway. To relate the PDF and lattice calcuable matrix elements, integral equations must be inverted using similar techniques to those employed by phenomenological analyses of 1 and 3 dimensional parton distributions. Moreover experimental and lattice results can be combined within this inverse problem to obtain better results than they could individually.

Transverse Momentum Distributions (TMDs) are three-dimensional maps of hadrons in momentum space and generalize the well-known concept of collinear Parton Distribution Functions (PDFs). TMDs are crucial in understanding the 3D spin and momentum structure of the nucleon and other hadrons, and information on their functional form can be obtained, for example, from Drell-Yan and Semi-Inclusive Deep Inelastic Scattering (SIDIS).

In this seminar I will discuss the state-of-the-art status of unpolarized TMD extractions, focusing on the results obtained by the Pavia group and in particular on the most recent global TMD extraction that reaches the perturbative accuracy of next-to-next-to-next leading log.

Over the last 20 years, there has been intense experimental activity dedicated to the measurement of observables to help build a 3D description of the nucleon. Generalized parton distributions (GPDs) describe complementary aspects of the structure of hadrons, providing qualitative and quantitative information about the partonic structure and dynamics such as orbital angular momentum. The formulations of the Deeply Virtual Compton Scattering (DVCS) cross-section are parametrized in terms of Compton Form Factors (CFFs) which are convolutions of GPDs with coefficient functions computed from perturbative QCD. The CFFs are extracted from DVCS experimental data taken at Jefferson Lab, including the most recent Hall A data. The analysis consists of a local fitting technique where the CFFs, ReH, ReE, and ReHtilde are determined independently in each kinematic bin for the unpolarized beam-target configuration at twist-2 approximation using the formalism developed by A.V. Belitsky, D. Müller, and A. Kirchner (BKM02 and BKM10). Significant systematic studies were done to optimize the local fitting procedure. The resulting CFFs are then used to train and regularize the neural network to obtain a global behavior of the CFFs with minimal model dependency. This procedure is tested and systematically studied using pseudo data generated with kinematics mimicking the experimental data.

The SpinQuest experiment (E1039) is a transversely polarized fixed target experiment at Fermi National Accelerator Laboratory designed to measure the sea-quark Sivers functions via the Drell-Yan process and the gluon Sivers function via the J/$\psi$ process. An unpolarized beam of 120-GeV protons will interact with a transversely polarized proton or deuteron target which will produce Drell-Yan and J/$psi$ dimuon events. Those muons will be detected in the spectrometer which allows for the extraction of the single-spin transverse asymmetry. Fast online monitoring is necessary to scan the quality of the incoming data and the general health of the experiment. Machine learning techniques can be used to speed the reconstruction of dimuon events on a spill-by-spill basis, and monitor the measured asymmetry over a longer period of time. Additionally, slow controls information can be integrated, allowing for automation of diagnostics and quality checks during the experiment, potentially reducing the overall systematic error of the experiment.

The Super BigBite Spectrometer (SBS) physics program at Jefferson Lab provides a large acceptance apparatus to precisely measure the proton and neutron form factors. The neutron electromagnetic form factors, \(G_E^n\) and \(G_M^n\), give important insights into the nucleon structure. The GMn experiment took place in fall of 2021, measuring \(G_M^n\) by colliding electrons on a liquid deuterium target, and extended the \(Q^2\) coverage from 5.0 to 13.6 GeV\(^2\). The GEn-II experiment will take place in August 2022, measuring \(G_E^n\) by colliding a polarized electron beam with a polarized \(^3\)He target, will extend the \(Q^2\) coverage from 3.5 to 10.2 GeV\(^2\). In both experiments Gas Electron Multiplier (GEM) based trackers will precisely measure the scattered electrons. GEM detectors are capable of rates higher than 500 kHz/cm\(^2\) with position resolutions of 70 \(\mu\)m. The proper running of these detectors is critical to the success of the SBS experiments. At our highest \(Q^2\) point we expect to be able to calculate the form factor ratio with an accuracy better than \(\Delta (G_E^n/G_M^n) = 0.20\), which corresponds to \(\Delta G_E^n = 3 \times 10^{-4}\) with accurate measurements of \(G_M^n\). This would greatly increase our understanding of the neutron in a region where no data is available.

Nuclear physics is a fascinating field that allows to probe the interactions between nucleons inside the nucleus using fundamental particles such as the electron or much larger and heavier objects like ions as magnifying glasses, allowing us to extract information about the how, why and what is happening inside nuclei. Yet, scientific discoveries have historically been rooted in the desire for some to take on a quest to tackle the unknown, often with relentless commitments and efforts, and sometimes bold actions that have proven to unravel new pathways. This talk will provide some brief review on the role and successes of (basic and applied) nuclear physics as they pertain to my journey in becoming a nuclear physicist, as well as establishing bridges to under-represented groups.

Lattice QCD can provide nonperturbative information about the three-dimensional structure of hadrons including TMDPDFs and their evolution. I will present recent exploratory lattice QCD calculations of the Collins-Soper kernel describing the rapidity evolution of quark TMDPDFs. I will also discuss the outlook for achieving lattice QCD predictions of the Collins-Soper kernel, and eventually complete lattice QCD predictions of TMDPDFs, with controlled systematic uncertainties and phenomenologically relevant precision.

I will outline the main problems involved in the interpretation of the flux-averaged neutrino-nucleus cross sections--the understanding of which is critical for the determination of neutrino oscillation parameters--and argue that the theoretical approach based on factorisation provides a unified framework, allowing to take into acount all relevant reaction mechanisms in a consistent fashion.

Transverse spin asymmetries that are observed in hadron production in DIS can be explained in the transverse-momentum-dependent (TMD) PDF approach as arising from correlations between the spin and the intrinsic transverse momentum of quarks and the spin of the parent nucleon.

These correlations should give rise to transverse spin asymmetries for example in the production of Drell-Yan muon pairs in the scattering of pi- off transversely polarized protons. The same effect could appear in J/psi production, though the magnitude depends on the production mechanism. COMPASS has collected data with pi- beam and transversely polarized NH3 target and the analysis of the J/psi production is in progress. The production of J/psi in muon-proton scattering on the other hand can proceed via the photon-gluon fusion process, gamma* g -> c cbar. Measurement of this process thus allows to access the gluon TMD PDFs. COMPASS has measured this process with transversely polarized proton target and the results will be presented.

Compton famously studied frequency shifts in the scattering of electromagnetic radiation in his Noble-prizewinning work. The so-called Compton effect provided one of the earliest experimental verifications of the existence of separate, individual photons in beams of electromagnetic radiation. Recently, prodded by the desire to construct intense narrowband sources of x-rays or gamma rays, photon sources based on the scattering of laser radiation from relativistic electron beams have been built and operated. Most present devices operate in regimes where linear (first order QED) calculations of the spectrum of the scattered radiation apply. In the future, however, when more intense lasers are available, non-linear Compton scattering obtains. A group at Old Dominion University has developed new methods allowing this more general case to be calculated precisely. After reviewing spectrum calculations in the context of some existing and contemplated Compton Sources, several new predictions involving non-linear Compton scattering will be presented. In particular, we have demonstrated through calculation that proposed performance enhancements in Compton sources by frequency chirping extend to the highest harmonics emitted from the source and are remarkably insensitive to being degraded by electron beam thermal effects.

I will talk about a global fit of the available polarized Semi-Inclusive Deep Inelastic Scattering (SIDIS), polarized pion-induced Drell-Yan (DY) and W/Z boson production data at N3LO and NNLO accuracy of the Transverse Momentum Dependent (TMD) evolution, and extraction of the Sivers function for u,d,s and and for sea quarks. The Qiu-Sterman function is determined in a model independent way via the operator product expansion from the extracted Sivers function. I will also show the study of the applicability region, the impact of the unpolarized distributions' uncertainties, the universality of the Sivers functions, positivity constraints, the significance of the sign-change relation, and provide the comparison with the existing extractions.

Geant4 is a software toolkit for simulating how particles interact with matter. It has a wide range of applications across diverse fields, with an emphasis on the simulation of physics experiments and events. It is an important tool in the preparation and analysis of many nuclear and particle physics experiments. The software is constantly evolving with the field, as a network of Geant4 working groups optimizes the structure of the code and the accuracy of the physics. In some aspects, the software is still a work in progress, leaving some gaps in its ability to simulate all experiments. One such piece of physics that is missing from the software is accounting for spin polarization in low energy neutron scattering. Spin-polarized neutrons scattered from nuclei will exhibit a left-right asymmetry in their scattering distribution. This behavior is not included in the Geant4 classes that handle low energy neutron scattering. Including the calculations for this left-right asymmetry is a key component of utilizing Geant4 for simulating polarized neutron experiments. In this talk, I will describe our work on implementing polarization effects for elastic neutron scattering in Geant4 and demonstrate some proof-of-concept results of the effect these modifications can have on simulations.

In the fall of this year in September, the Jlab Hall-A SBS program is sched-uled to start running. The primary goal of the program is to measure elastic-electromagnetic form factors of the nucleon with high precision at high Q² values. The knowledge of the electromagnetic form factors are essential for our understanding of the structure of the nucleon. The concept of the Hall-A SBS (Super Bigbite Spectrometer), which has a large solid angle acceptance (∼ 75 msr) and the capability to operate at high luminosity, relies on Gas Electron Multiplier (GEM) detectors for particle tracking. In this talk, I will talk about how the GEM detectors will be used in the SBS program, and the commissioning activities of the UVA-built GEM detectors that are underway at the Jefferson Lab, in order to make them ready for the upcoming experiments. Also, I will briefly talk about the Jlab-SBS program with a special focus on its very first experiment - GMn : precision measurement of the magnetic form factor of the neutron up to Q² = 13.5 (GeV/c)² using the ratio method.

TMDs are fundamental objects in the study of three-dimensional structure of nucleons. However, due to their nonperturbative nature, they cannot be directly computed and have to be extracted from experimental measurements. In this talk we will present the formalism and methodology involved in this analysis and give an overview of the most recent results.

In this talk I will outline some fundamental properties of transverse-momentum-dependent distributions (TMDs), in particular their role in exploring the structure of hadrons in 3D momentum space. I will also focus on some open issues, and on the possibilities to deepen our understanding of hadron structure and hadronization by combining the potential of fixed-target and collider experiments.

Hadronization is the process of a liberated quark traversing the nuclear medium and its formation into a color neutral object.  This talk will focus on the color propagation experiments in Hall B to study the hadronization process.  Hall B is one of the four experimental areas at the Thomas Jefferson National Accelerator Facility (JLab). The original experiment used deep inelastic electron scattering to liberate a quark from a bound nucleon and the CLAS6 detector to count the multiplicity of produced hadrons and measure the transverse momentum broadening in order to understand the hadronization process.   The experiment ran during the CLAS6 period (1997-2011) before the JLab energy upgrade to 12 GeV.  For CLAS12, new reconstruction software, file format, and analysis framework have been developed.  With a grant from the DOE, my students and I developed software to convert the CLAS6 files into the CLAS12 format where I have used the new analysis framework to data mine the old data.  Preliminary color propagation results for protons and mesons will be presented.

The proton is commonplace in the world but contains rich information about how matter is constructed by the strong force.  It is described by the parton picture, namely a system made of quarks, antiquarks and gluons, when it is observed in short range such as high-energy scattering.  The proton is the best object to investigate the dynamics of the strong force (i.e. QCD) since it is the simplest stable system bound by the strong force.  Particularly the antiquarks in the proton are of great interest because they are all dynamically created by the strong force.  They are thus sensitive to mechanisms beyond the simple quark model where the proton is composed of only three quarks.

SeaQuest is a fixed-target experiment using the 120-GeV proton beam at Fermilab.  It detects the Drell-Yan process in proton + proton and proton + deuteron scatterings; quark + antiquarks -> gamma^* -> mu^+ + mu^-. It primarily aims at measuring the flavor asymmetry of light antiquarks, namely the difference between antiup and antidown quarks in their distributions in the proton.  Several mechanisms that can induce this asymmetry have been theoretically proposed.

In this seminar, the physics motivation and the measurement principle of SeaQuest are explained.  Then the detector construction, data analysis and experimental results are presented.

The RMS radius of the neutron distribution in a heavy nucleus RN provides an important test of nuclear theory. Furthermore RN is used in the determination of the density dependence of symmetry energy of neutron rich matter; this dependence is an important input in neutron star structure, heavy iron collision and atomic parity violation experiment calculations. In the past hadron scattering experiments with with pion, proton or anti-proton beams have been used to determine the neutron radii of heavy nuclei. However, these measurements suffer from uncertainties associated with the probe particle and the target nucleus. Electron scattering provides a model independent probe of nuclear radii. However, in electron scattering, the measurement of neutron distribution in a nucleus is much harder than the measurement of the proton distribution since the neutron is uncharged. Because the neutron weak charge is much large than that of the proton, PRex-II used the parity violating weak neutral interaction to probe the neutron distribution in the 208Pb nucleus, thus measuring the RMS neutron radius with high accuracy. The PRex-II experiment was performed from June to September 2019 in Jefferson lab experimental hall A using the High Resolution Spectrometer (HRS) pair. This seminar presents the details the PRex-II experiment as well as the preliminary results from HRS Optics calibration measurements and from the Gas Electron Multiplier (GEM) detectors used for obtaining high rate calibration data.
 

Using electron scattering data from SLAC E139 and muon scattering data from NMC in the DIS region, we determine the F₂^A/F₂^p and F₂^A/F₂ⁿ structure function ratios, spanning 0.07 < x_B < 0.7 and 1 < Q² < 200 GeV/c² and 0.006 < x_B < 0.6 and 1 < Q² < 55 GeV/c², respectively. This region is of particular relevance to studies of EMC Effect. Assuming no Q² dependence, we compare the structure function ratios for isoscalar nuclei and study non-isoscalar nuclei with the possibility to look for flavor dependence. This talk will present the results of the mentioned ratios for isoscalar nuclei using the new F₂ⁿ global data from the CTEQ-JLab Collaboration.

The Muon g-2 experiment at Fermilab (E989) is addressing the known, but not yet understood incompleteness of the Standard Model (SM) theory by measuring the anomalous magnetic dipole moment, a_m, defined as (g_m-2)/2. To be able to test the SM predictions, the experiment aims to reach the precision of 0.14 ppm. At Fermilab a intense proton beam is passed through a target where pions are produced; after a long delay virtually all pions decay into muons, which are stored in a muon storage ring. Evaluation of a_m requires the measurement of the muon spin precession frequency in the storage ring and, of the mean magnetic field the stored muons experience. I will introduce the experiment, its basic measurement techniques, and will focus on the magnetic field measurement, my thesis topic. The basic method relies on the free induction decay (FID) signals from NMR probes. Of particular interest is understanding and quantifying the possible interference between the electrostatic beam focusing quadrupoles and the FID signals in the 378 "fixed" NMR probes mounted all around the storage ring.

E12-10-002 ran in Hall C in Spring of 2018 for about 3 weeks with the goal of extracting cross sections for H(e,e') and D(e,e') reactions in the deep inelastic and resonance region regimes. Our data cover a broad range in Bjorken x and we reached Q^2 values as high as 14 GeV^2. E12-10-002 will have an impact on a wide range of physics topics like Parton Distribution Functions extractions, Quark-Hadron Duality studies, F2_neutron/F2_proton at large x, modeling of H(e,e') and D(e,e') processes and moments of the F2 structure function.

In this talk I will summarize the physics motivation for running the experiment and I will also highlight the sinuous path to getting precision cross sections from measurements done with a brand new spectrometer (Super High Momentum Spectrometer) and a new data acquisition system.

An overview of the physics of Wigner Distributions will be presented within the context of the recently established  Jefferson Lab Center for Nuclear Femtography.

Imaging the 3D partonic structure of the nucleon is a fundamental goal of every major nuclear experimental program, including the EIC. Ji first proposed Deeply Virtual Compton Scattering (DVCS) as a probe for understanding the spatial distribution of the partons by fourier transform of the exchanged momentum transfer between the initial and final proton. The extraction of observables from Deeply Virtual Exclusive Reactions in a clear and concise formalism, such that the various twist components and angular dependencies can be untangled, is key. We present a completely covariant description of the DVCS process that can be extended to any kinematics, either fixed target or collider. In our helicity formalism, we extract our observables such that the dependence on Q2 is clear. We can separate kinematic twist, characterized by subleading dependence on 1/Q2, from the dynamic twist, given by the Q2 suppression and azimuthal angle ɸ. Since the higher twist terms are characterized by their dependence on ɸ, it is important to understand the angular contribution arising from the kinematic variables and separate it from the characteristic angular dependence of the higher twist terms. The extension to other Deeply Virtual Exclusive Reactions, such as TCS, is in progress. From our formalism, one can extract observables important in understanding the physical properties of the proton such as the angular momentum of the quarks and gluons inside of the proton.

The ultimate goal of my research is to measure for photons between 8 and 20 MeV using a frozen-spin target originally constructed at CERN in the mid 1970’s. The goal is to 1) look for a dibaryon state of the deuteron and to 2) investigate suspected deviations of the Gerasimov-Drell-Hearn integrand. In order to make sure we are as prepared as possible, we practice operation of the target in our lab. The primary goal of these practice runs or “cooldowns” is to achieve the ideal ratio of Helium-3 and Helium-4 in the target chamber of our dilution refrigerator in order to get it down to the coldest temperature possible and then to measure the polarization of the target. However, we have hit a few bumps along the way, and cannot currently do cooldowns due to our dilution fridge leaking. The primary focus of my talk will be on the steps we have taken to fix our fridge and get back to doing proper cooldowns.

Parity-violating electron scattering provides a clean probe of neutron densities that is model independent and free from most of the strong interaction uncertainties. The PREX-II and CREX experiments at Jefferson lab aim to measure the nucleon skin thickness in 208Pb and 48Ca via parity violating electroweak asymmetry in the elastic scattering of left and right polarized electrons. These measurement from Pb and Ca are sensitive to the existence of this neutron skin and it will provide information on nuclear structure. Knowledge of difference in proton and neutron radius or an effective neutron skin thickness is required in order to calibrate the equation of state for neutron rich nuclear matter.

I will discuss how we are getting ready for the upcoming 2019 runs of both experiments, especially focused on source studies and polarimetry studies.

Two types of functions used to describe the electromagnetic structure of nucleons include “form factors”, which describe the spatial distribution of charge and magnetism within the nucleon, and “structure functions”, which describe their longitudinal momentum distribution. We explore form factors by exclusive scattering of high energy leptons with the nucleus or focusing on elastic channels in our analysis; we explore structure functions by inclusive scattering with the nucleus. When exploring the electromagnetic structure of the neutron, ³He is an ideal target for quasi-elastic scattering because the proton-proton wave-function is dominated by the spin-zero, S-state (by approximately 90%). Thus, scattering leptons from a polarized ³He target is a reasonable approximation to scattering from a polarized, free neutron.

My talk will focus on the polarizable ³He targets used in two experiments at Jefferson National Laboratory: one experiment explores the neutron electric form factor, G_E­ⁿ, and the other experiment explores the neutron structure function, A₁ⁿ. I will discuss my work in the filling and characterization of these targets as well as optimizing these targets for future experiments at higher beam energies.

The PREX-II and CREX experiments are both parity-violating electron scattering experiments which seek to probe the weak form factor of the nuclei of 208Pb and 48Ca respectively by measuring an asymmetry between the scattering of left- and right-handed electrons. These experiments seek to constrain models of nuclear theory by measuring the radius of a “neutron skin” in neutron-rich nuclei. There are a number of experimental challenges associated with these very high luminosity, high precision measurements. I will discuss how we will meet these challenges in the upcoming 2019 runs of both experiments.

Possibility to use high intensity secondary beams at the SPS M2 beam
line in combination with the world’s largest polarized target, liquid hydrogen,
liquid deuterium and various nuclear targets create a unique opportunity
for universal experimental facility to study previously unexplored aspects
of meson and nucleon structure, QCD dynamics and hadron spectroscopy. 

High intensity hadron (pion dominated) beams already made COMPASS the
world leading facility for hadron spectroscopy and  hadron structure
study through Drell-Yan production of di-muon pairs. High intensity
muon beams, previously used for unique semi-inclusive and exclusive
hard scattering programs, make possible proton radius measurement in
muon-proton elastic scattering and further development of polarized
exclusive hard scattering program.
  
Upgrades of the M2 beam line resulting in high intensity RF-separated
anti-proton- and kaon-beams would greatly expand the horizon of experimental
possibilities at CERN: hadron spectroscopy with kaon beam, studies
of transverse momentum dependent quark structure for protons, pions and
kaons, precise studies of nuclear effects and for the first time measurements
of kaon quark—gluon substructure.

Since the failure of classical mechanics at subatomic scales, understanding the spin of fundamental particles has been central to the investigation of the most basic workings of matter. Beyond a key property for study, spin has become an indispensable instrument for experimental discovery in the form of polarized beam sources and scattering targets. As physicists have turned from the successful description of the weakly bound, perturbative regime of QCD toward unraveling the mysteries of confinement and the glue, ever-improving polarized tools are as crucial as ever. This talk will give an overview these tools, emphasizing solid polarized targets for leptonic probes of QCD, covering their operation, development and upcoming experimental use. With the promise of a nuclear physics facility for e-N collisions on the horizon, I will discuss a new technique to produce a polarized He3 beam source. Finally, a new search for exotic glue in the nucleus using polarized targets and sources will be introduced.

The UVA solid polarized target group has been a hub for scattering experiment
polarized target research for the last 30 years.  Solid state polarized targets provide
high polarization and high density for many types of fixed targets employed by nuclear
labs worldwide.  Dynamic nuclear polarization and other RF techniques are
used to enhance the polarization of the cryogenically cooled solid
material to improve the figure of merit of the experiment.  An overview of
the technology and techniques is given with an emphasis on recent
developments.  Some future experiments are discussed providing examples of
implementation of this research which make it possible to access many spin-dependent
degrees of freedom used to test fundamental prediction of QCD.

 

Color Transparency (CT) refers to a prediction of QCD that at high momentum transfer Q^2, a system of quarks, each of which would normally interact very strongly with nuclear matter, could form a small color-neutral object whose compact transverse size would be maintained for some distance, passing through the nuclear medium undisturbed. A clear signature of CT would be a dramatic rise in nuclear transparency with increasing Q^2. The existence of CT would contradict traditional Glauber multiple scattering theory in its domain of validity, which predicts constant nuclear transparency. CT is also a prerequisite to the validity of QCD factorization theorems, which provide access to generalized parton distributions that contain information about the transverse and angular momenta carried by quarks in nucleons. The E12-06-107 experiment in JLab's Hall C will look for a signature of CT in electron-proton scattering with carbon-12 and liquid hydrogen targets. Data for Q^2 between 8 and 14 GeV^2 were taken in early 2018 in JLab's Hall C, a range over which nuclear transparency should differ appreciably from conventional Glauber calculations.

 

I will share two applications of spin-polarized noble gas imaging using magnetic resonant imaging. To date, self-sustained fusion energy production has not been achieved since the energy spent in containing the plasma favorable for fusion reaction surpasses the energy outcome. Spin-polarized fusion (SPF) promises a 50% boost in fusion cross section between deuterium and tritium (or He-3). However, SPF has not been experimentally tested in a reactor for several logistical challenges related to delivery of polarized fuels to the plasma.

In collaboration with General Atomics and JLab, we propose to optimize and measure polarization survival of spin-polarized He-3 during permeation into polymer-shelled inertial-confinement fusion (ICF) pellets, a crucial step toward achieving SPF. Granted that adequate polarization survival into the pellets is achieved, the SPF reaction of D and 3He will be tested in the General Atomics D-III D Tokamak which would be the very first experimental demonstration of SPF in a fusion energy reactor.

CT has been the golden standard imaging technique to characterize and quantify emphysema, however, it exposes the body to ionizing radiation. An alternative image based method of characterizing emphysematous lung tissue is by having the patient inhale spin-polarized noble gas (He-3 or Xe-129) and image the gas inside the lungs. Since diffusion of the gas molecules inside the lungs are constrained by the microstructure of the lungs, how far gas molecules travel can tell us about regional tissue destruction due to emphysema. Here we introduce a novel method of defining emphysema index based on apparent diffusion coefficient maps acquired using a diffusion-weighted MRI pulse sequence.

The MOLLER experiment at Jefferson Laboratory will be part of a new generation of ultra high precision electroweak experiments. It will measure the Moller (electron-electron scattering) parity-violating asymmetry, providing an unprecedented precision on the electroweak mixing angle. To achieve such small uncertainties, innovative techniques in the electron source are required to switch the beam helicity more quickly than previously achievable. A key technology is the Pockels cell in the laser optics of the polarized electron source. RTP crystals have been demonstrated to achieve almost an order of magnitude faster transition times than commonly used KD*P crystal cells and are promising for the future Moller Experiment. 

The CUORE experiment, a ton-scale cryogenic bolometer array, recently began operation at the Laboratori Nazionali del Gran Sasso in Italy. The array represents a signi cant advancement in this technology and exceeds the size of previous experiments of this type by more than ten fold. In this talk we give an overview of the design and performance of the detector and present the results from a high-sensitivity search for a lepton-number{violating process: 130Te neutrinoless double-beta decay.

The study of nuclear beta decay has been at the forefront of our current understanding of the physical landscape, and continues to play an essential role in the search for beyond Standard Model physics. In order to separate the wheat from the chaff of the myriad possible theoretical extensions, a reliable estimate of the Standard Model contribution is indispensable. Recently, the description of the allowed beta spectrum shape was revisited and extended in order to tackle these challenges. Besides the study of the fundamental nature of the weak interaction, the beta spectrum shape is an essential ingredient in several outstanding problems in particle physics, such as the reactor antineutrino anomaly. We will provide an overview of the current state-of-the-art and its challenges, and discuss its implications on the reactor anomaly and behavior of geo-neutrinos.

The proton charge radius is one of the most fundamental parameter in physics. Precise knowledge of its value is critically important in various physics field.

Recent high precision measurement of proton radius using the spectroscopy method of muonic hydrogen atom demonstrated a much smaller value, which is more than 5 standard deviations away from the widely accepted CODATA value. This fact triggered the well known “proton charge radius puzzle”.  In order to investigate this puzzle, the PRad experiment was performed in 2016 at Jefferson Lab in Hall B. This experiment aims to extract the electric form factor in an unprecedented small four-momentum transfer squared region, from  \(2 \times 10^{-4}\) to \(10^{-2} (GeV/C^2)\), with sub-percent precision.

The PRad experiment utilizes a pair of large area, high spatial resolution GEM detectors, and a non-magnetic calorimeter (HyCal). PRad experiment has superior ways to control systematic errors, the e-p elastic scattering cross-section will be normalized to the well known moller scattering process, which is simultaneously measured with similar kinematics and the same appratus, this greatly reduces the uncertainties from luminosity, detector efficiency and acceptance, etc; and PRad covers a large \(Q^2\) range in one experimental setting. With the data in low \(Q^2\) region, we hope to reach sub-percent precision and model independent extraction of proton charge radius.

In this talk we will present the detailed experimental method and setup, and the current data analysis status.

The unique Fe vacancy ordering in alkali metal doped iron selenide \(A_xFe_{2-y}Se_2\) (A=K, Rb, Cs, \(\cdots\)) has drawn a lot of attention among the Fe-based superconductor community. In this work we investigated the effects of annealing on Fe vacancy in \(K_xFe_{2-y}Se_2\) single crystal samples by high energy X-ray diffraction and Monte Carlo simulation. The X-ray results indicated that the I4/mmm phase volume fraction decreased after annealing, while the simulation results demonstrated that this shrink of I4/mmm phase is accompanied with a expand of the Fe vacancy disordered area at the domain boundaries. Together with the well known annealing induced superconductivity enhancement, we found that superconductivity in this system is most likely related to the Fe vacancy disordered region.

Strongly self-interacting dark matter (SSIDM) was proposed as a candidate which might be able to solve astrophysical problems plaguing collisionless cold dark matter: the cusp-vs-core, the missing satellite and the too-big-to-fail problems. These SSIDM particles can in principle form bound states. In particular, if the SSIDM particles belong to a confining gauge group, the singlet states (similar to the baryons of QCD but whose spin depends on the gauge group), the so-called dark "baryons", can cluster into astronomical compact objects which will be called Dark Astronomical Extreme Compact Objects (DAECO) in this paper. How massive can they be? What are their typical sizes? Depending on the mass of the dark baryon, a DAECO can be as "large" as 33 Earth mass for a 1-TeV dark baryon to 0.3 Earth mass for a 10-TeV dark baryon. These DAECOs are extremely small: 15 cm for the 33-Earth mass DAECO and 1.5 mm for the 0.3-Earth mass one. These planetary-mass-type DAECO’S could be "detected" for using techniques such as the astrometric measurements as applied to the searches for exoplanets. Specifically, one would look for gravitational influences of DAECOS’s on a given star when they come close to it. The search for DAECO’s, if they exist, would provide a "direct" detection of strongly self-interacting dark matter at an astronomical level, somewhat similar to laboratory direct detection searches through the detection of nuclear recoil. Another possibility is the merger of two clusters of DAECOs with each having a mass ∼ 30 M generating gravitational waves of the types observed by LIGO.

The electromagnetic form factors of the nucleon are essential for our understanding of the structure of the nucleon. Precision measurements of nucleon form factors is a fundamental part the Je erson Lab experimental program. The 12 GeV beam upgrade and the newly designed Super BigBite Spectrometer make possible a new generation of experiments to measure nucleon form factors with high precision at high Q2 values around 10 GeV2. The concept of the Super BigBite Spectrometer, which provides large solid angle and the capability to operate at  high luminosity, is based on new Gas Electron Multiplier (GEM) detector based particle trackers. The SBS GEM chambers are expected to provides a good position resolution of 70 m, while operating in high rate conditions up to 0.5 MHz=mm2. A set of 40 GEM detectors, each with an active area of 60x50 cm2, has been built in the GEM detector lab at UVa for the the proton polarimeter trackers of SBS. This seminar will present an overview of SBS nucleon form factor experiments and will report on the Research, development and testing of SBS GEM chamber data acquisition system which is essential to make those high rate experiments possible.
 

Stars freeze. But not all of them. Only some parts of some stars will. In white dwarfs and neutron stars, despite temperatures of millions of degrees, the densities and pressures are great enough to compact nuclei into a crystalline lattice millions of times more dense than any material on earth. Deeper still in neutron stars, near the nuclear saturation density, nuclei begin to touch and rearrange into non-spherical structures called 'nuclear pasta.' To interpret observations of neutron stars the composition and structure of the crystal and pasta layers must be understood, as the microscopic properties of the crust determine the macroscopic properties of the star, such as its thermal and electrical conductivity. At Indiana University, we perform computer simulations of these exotic astromaterials to calculate the physical properties of these stars.

The ratio of decay rates \(\Gamma(\pi{\to}ev^{-}(\gamma))/\Gamma(\pi{\to}{\mu}v^-(\gamma))\) provides a key confirmation of the V−A nature of the electroweak interaction. Currently, the experimenally determined value of this ratio is\(R^{exp}_{e/\mu} = (1.230\pm0.004)\times10^{-4}\), whereas the theoretically determined value according to Standard Model physics is \(R^{SM}_{e/\mu} = (1.2356\pm0.0001)\times10^{-4}\). This \(\pi_{2e}\) branching ratio proves one of the most sensitive tests for lepton universality. The branching ratio can also be used to give mass bounds on “new” , or non V−A, particles e/µ and interactions. It is for this reason the PEN group, an international collaboration led by University of Virginia, has undertaken to measure \(R^{exp}_{e/\mu}\) to a precision of 5 × \(10^{-4}\) or better. I will discuss the challenges and analysis techniques to extract \(\pi_{2e}\) branching ratio with more emphasis on the Monte Carlo simulation that aids in determining necessary quantities for branching ratio extraction.

 

The Nab collaboration at the Spallation Neutron Source (SNS) aims to measure the electron-neutrino correlation parameter "a" with a relative uncertainty of about 10^{-3}, and the Fierz interference term "b" with absolute uncertainty of 3 x 10^{-3}. Nab will use a novel "time of flight" (TOF) EM field spectrometer and segmented Si detectors. The scientific motivation is to provide an independent measurement of the ratio of axial-vector to vector coupling constants of the nucleon to an uncertainty of 0.03% and to test the unitarity of the CKM quark mixing matrix. In the Nab experiment, "a" is determined by combined precise determinations of the electron energy and the proton time of flight. In this talk, we present the motivation of the Nab experiment, the principle and the uncertainty analysis of the measurement of “a”.

The Nab experiment is designed to a) determine the ratio of axial-vector coupling to vector coupling to an uncertainty of 0.03% error, b) test the unitarity of CKM Matrix and c) measure the Fierz interference term b by studying free neutron beta decay. In neutron beta decay, the electron energy spectrum is modified by the Fierz interference term. Therefore, a precise measure of  the electron energy spectrum could lead to an excellent determination of b. The Nab experiment is expected to measure the Fierz interference term with an uncertainty of about 10^-3. We present the uncertainty analysis of the electron energy spectrum, and show the required limit of the experiment uncertainty in different aspects.

 

Coulomb Sum Rule states that the integration of longitudinal response of a nucleus over the range of energy excitation dominated by quasi-elastic proton knock-out process should be equal to the total number of protons in the nucleus.

The test of Coulomb Sum Rule will shed light on the question of whether or not the properties of nucleon are modified in the nuclear medium.

In order to test the Coulomb Sum Rule in nuclei, a precision measurement of inclusive electron scattering cross sections in the quasi-elastic region was performed at Jefferson Lab.

Incident electrons with energies ranging from 0.4 GeV to 4 GeV scattered from 4He, 12C, 56Fe and 208Pb nuclei at 4 scattering angles(15,60,90,120 degree) and momentum transfer ranging from 0.55 GeV/c to 1 GeV/c.

After complete all the data analysis, we expect to confirm/refute the presently controversial issue of the quenching of the longitudinal response function in medium weight nuclei and as importantly investigate the |q| evolution of the Coulomb Sum Rule as we probe significantly shorter distances.

Time reversal symmetric topological superconductors in three spatial dimensions carry gapless surface Majorana fermions. They are robust against any time reversal symmetric single-body per- turbation weaker than the bulk energy gap. We mimic the massless surface Majorana’s by coupled wire models in two spatial dimensions. We introduce explicit many-body interwire interactions that preserve time reversal symmetry and give energy gaps to all low energy degrees of freedom. We show the gapped models generically carry non-trivial topological order and support anyonic excitations. 

Analysis of the Drell-Yan process in high energy polarized proton-proton collisions is a unique method for probing the proton spin structure. Measurement of the longitudinal double spin asymmetry ($A_{LL}$) in the Drell-Yan process provides clean access to the anti-quark helicity distributions without involving quark fragmentation functions. In the PHENIX experiment at RHIC, the Forward Silicon Vertex Detector (FVTX), together with forward muon spectrometers, allows us to study the Drell-Yan process by detecting the muon pairs in the forward region (1.2 $< \eta <$ 2.4) while also suppressing backgrounds due to heavy-flavor production. In this talk, the Drell-Yan $A_{LL}$ measurement for the intermediate mass region (4.0 GeV $< M <$ 8 GeV) using the RHIC 2013 data of proton-proton collisions at a center of mass energy of 510 GeV is presented.

I will present the PHENIX measurements for the cross section and double-helicity asymmetry (ALL) in inclusive π0 production at midrapidity from p + p collisions at √s = 510 GeV from data taken in 2012 and 2013 at the Relativistic Heavy Ion Collider. The next-to-leading-order perturbative-quantum chromodynamics theory calculation is in excellent agreement with the presented cross section results. The calculation utilized parton-to-pion fragmentation functions from the recent DSS14 global analysis, which prefer a smaller gluon-to-pion fragmentation function. The π0 ALL results follow an increasingly positive asymmetry trend with pT and √s with respect to the predictions and are in excellent agreement with the latest global analysis results. This analysis incorporated earlier results on π0 and jet ALL and suggested a positive contribution of gluon polarization to the spin of the proton ΔG for the gluon momentum fraction range x > 0.05. The data presented here extend to a currently unexplored region, down to x ∼ 0.01, and thus provide additional constraints on the value of ΔG.

Recent Muonic hydrogen measurements have determined the proton's charge radius to be 0.84fm, a result systematically different from both the atomic hydrogen results and electron scattering results of ~0.88fm.  In an effort to under this "puzzle",  I will present, from a historical perspective, how the proton's charge radius has been  extracted from electron scattering data starting with the 1963 review article by Hand et al., with its 0.81(1)fm standard dipole radius and working my way to up the ~0.88(1)fm 2014 results from Mainz.   I will then discuss why groups in Virginia (JLab, UVA, and W&M) are extracting a radius very close to the Muonic result as well as discuss some of the pitfalls of multivariate fitting.

I will review the new cross section and charge radius results from the Jefferson Lab’s “LEDEX” experiment. This experiment includes measurements on several light nuclei, hydrogen, deuteron, lithium, boron, and carbon with beam energies down to 360 MeV and spectrometer angles down to 12.5 degrees. To test our ability to measure absolute cross sections, as well as our ability to extract the charge radius, we first testd our technique against the extremely well measured 12C case and found excellent agreement using the Fourier-Bessel parameterization. Our new results on boron (2.40 ± 0.12 fm) and lithium (2.52±0.05 fm) are in nice agreement with model independent variational monte carlo calculations. For the lightest nuclei, we clearly see the limits of this technique and will show why for those nuclei the radius is not determined from a Fourier-Bessel technique but by determinining the slope at q2 = 0.

Sensitive searches for time reversal violation in many different systems are very important scientifically to probe physics beyond the Standard Model and to search for processes which could help explain the matter-antimatter asymmetry of the universe.

We discuss the possibility of exploiting the already-observed large amplifications of neutron-nucleus parity violation  to search for T-odd effects in polarized neutron transmission through polarized targets.

Parity Violating Electron Scattering (PVES) is an extremely successful precision frontier tool that have been using for testing the Standard Model (SM) and understanding nucleon structure. Historically, 1978 pioneering Prescott experiment at SLAC was the first successful PVES experiment that confirmed the electroweak theory of particle physics developed by S. Glashow, S. Weinberg and A. Salam as the SM of the particle physics. Several generations of highly successful PVES programs (SAMPLE, A4, HAPPEX, G0 and SLAC E158 programs) have contributed to understanding of nucleon structure and testing the SM.

But missing phenomena like matter antimatter asymmetry, neutrino flavor oscillations, and dark matter and energy suggest that the SM is only a “low energy” effective theory.

Precision PVES measurements of SM predicted quantities can be used to constrain or discover new physics models beyond the SM. In nuclear physics the “EMC effect” has not yet been properly explained. Therefore an important question in hadronic physics is how protons and neutrons are modified when they are bound in a nucleus. A precise measurement of the neutron skin thickness which is a fundamental test of nuclear theory, will pin down the density dependence of the symmetry energy of neutron rich nuclear matter which has impacts on heavy ion collisions and neutron stars. The current and next generation PVES experiments will provide answers to these questions. Qweak and SoLID­PVDIS will provide a precision test of the Standard Model through an unique constraints on neutral electron­quark effective couplings while MOLLER will provide same through neutral electron­electron coupling. The Lead Radius Experiment PREX will provide a clean measurement of the neutron skin thickness. I will introduce PVES experimental techniques and discuss current generation PVES Qweak and PREX experiments and next generation PVES SoLID­PVDIS and MOLLER experiments.

For SoLID

A new proposal to measure parity violating deep inelastic asymmetry (PVDIS) will provide a precision test of the Standard Model through an unique constraints on axial­vector neutral electron­quark effective couplings and a precision measurement of the weak mixing angle. We plan to measure the asymmetry to about $\rm 0.5 \% $ precision over the Bjoken x from 0.3 to

0.7 where the PV asymmetry is approximately independent of hadronic structure. If any deviations observed, the residual hadronic and new physics contributions in the asymmetry could be separated by kinematic dependence of the PVDIS asymmetry. At the proposed precision level, asymmetry will be sensitive to novel hadronic structure effects including charge symmetry violation (CSV) effects and higher twist effects. Observation of these effects itself will be beneficial to building better theoretical models. A deuterium target will be used for Standard Model tests while a d/u quark distribution ratio measurement is proposed using a hydrogen target.

The broad reach in kinematic and high statistical precision at which PVDIS asymmetries are planned to measure, a large angle acceptance, high luminosity, and large azimuthal acceptance device is a necessity. We are proposing a new spectrometer based on a solenoid magnet called Solenoidal Large Intensity Device (SoLID) that will provide broad range of electroweak and QCD physics measurements to be conducted at the Jefferson Laboratory. The apparatus will have set of tracking gas electron multiplier (GEM) detectors, a gas Cerenkov detector, and a sampling electromagnetic calorimeter to provide particle identification. The experiment will be conducted as a high rate counting mode experiment.

Over the past two decades, the availability of a large body of electron-nucleus scattering data of unprecedented accuracy has triggered the development of highly refined theoretical approaches, based on realistic descriptions of both nuclear structure and the nuclear electromagnetic current, which have proved remarkably successful in explaining the experimental results. The extension of these approaches to the study of neutrino-nucleus interactions is needed to clarify a number of outstanding issues in both neutrino physics and astrophysics. I will discuss the results of recent work, aimed at developing a unified description of neutrino-nucleus interactions in the energy range extending from the few MeV region, relevant to astrophysical applications, to the few GeV region, relevant to long-baseline neutrino oscillation experiments.

The NPDGamma Experiment measured the parity violating gamma asymmetry from polarized neutrons captured on protons at the Spallation Neutron Source at ORNL. This parity violating asymmetry is proportional to the isovector contribution of the hadronic weak interaction (HWI) and has been measured to a precision of 13ppb which can help resolve the unconstrained coupling space of the HWI. As one of the parallel analyses of NPDGamma, we present a statistically optimal algorithm using a least squares fit to the 60Hz neutron pulses in order to filter, and make high level cuts on, production data.

Frequently small signals of interest are overwhelmed by background, systematic uncertainty, or statistical limitations. These types of constraints can degrade the quality of the observables under investigation. In some cases it is possible to improve the figure of merit using analytical tools while in others an experiment must be tactfully designed with error mitigation in mind. For a demonstration in error minimization in data analysis some branching ratios of the electromagnetic decays of the lower mass strange baryons are extracted using data from the CEBAF Large Acceptance Spectrometer (CLAS) detector in Hall B at Thomas Jefferson National Accelerator Facility. Some further examples are used for other experimental Halls as well as applications to systematic error minimization and plausible beam time reduction for polarized target experiments.

Jefferson Lab experiment E05-017 was designed to study 2-photon exchange contributions to elastic electron-proton scattering over a wide kinematic range. By detecting the scattered proton instead of the electron these measurements will be very sensitive to the epsilon dependence of the cross section and consequently the ratio of the electromagnetic form factors. The goals of the experiment, the experimental technique and the kinematic range will be presented. The analysis sequence and results of the early steps will be outlined.

The decay of the free neutron is the archetypal charged current semi-leptonic weak process. As such, experimental investigation of the decay process through lifetime and decay correlation measurements provide insight into a wide variety of physics, ranging from fundamental interactions to the formation of the early Universe. I will discuss some of the history of neutron decay measurements, the neutron lifetime's role in big bang nucleosynthesis, and my work on the upcoming in-beam measurement of the neutron lifetime at the NIST Center for Neutron Research.

Short Range Correlations (SRCs) have been recognized as responsible for the high momentum tail of the nucleon momentum distribution. Several experiments at Jefferson Lab have exploited inclusive scattering to study about SRCs by going to X_bj >2. In an upcoming tritium experiment (E12-11-112) we will perform a precision test of isospin dependence of two-nucleon short-range correlations using mirror nuclei: 3He and 3H. The data taken at x>2 will also be used to study three-nucleon short-range correlations. In this talk we will briefly present the motivation for this experiment as well as some of the experimental details and the expected results. In addition, we will discuss a method to check the absolute target thickness of sealed tritium cell through elastic scattering measurement.

Parity violation (PV) was first observed in semileptonic beta decays, and has been mapped out precisely at the quark and lepton level as part of the standard model. However, PV in hadronic systems has proven much more elusive, where the strong interaction dominates by seven orders of magnitude. These weak contributions have been classified in chiral effective field theory in terms of the spin and isospin dependence of transition amplitudes involving S and P waves. There is an active program to determine the EFT parameters by measuring hadronic PV using cold neutron beams at the Spallation Neutron Source (ORNL) and the NCNR reactor (NIST). These experiments use only few-body observables, for which nuclear wave functions are calculable. The NPDGamma experiment recently completed taking data of the PV gamma spin asymmetry in the reaction n + p -> d + gamma. We have commissioned the follow-up experiment n3He to measure the proton spin asymmetry in the reaction n + 3He -> 3H + p. These two experiments, along with elastic PV proton-proton scattering, will help isolate the four dominant contributions to the PV hadronic weak interaction.

The spin of the proton is a source of great mystery: how do the spins and other angular momentum of gluons and quarks add up to the spin of the proton? The so called 'spin puzzle' came up because the measurement of the valence quarks spin (EMC experiment at CERN, 1987) was found to be way smaller than the expected 0.5 (spin of the proton). My research focusses on the theory describing the component of angular momentum generated by motion of quarks and gluons (partons). This includes working with different types of distribution functions such as the regular Parton Distribution Functions, Generalised Parton Distribution Functions and Transverse Momentum Distributions. In my talk, I will highlight how we describe partonic angular momentum using these distributions and how we approach the problem of measuring it experimentally.

Critical behavior and phase transitions are of great interest in condensed matter physics. In this talk we introduce the basic concepts about criticality, as well as theoretical and numerical tools to study critical phenomena. The Landau-Ginzburg theory, or the "Order parameter" picture has been successful in describing many systems with second order phase transitions, for example in superconductors. But here we'll also see a 2D modified XY model that has phase transitions that doesn't not fit into the traditional description.

 

* Refreshments will be available at the talk.

QCD has provided the theoretical ground for the two leading classes of dark matter candidates:

WIMPS and axions. However, both have remained elusive to direct detections. In this talk, I will show that QCD can inspire us further on the quest for dark matter. I will discuss the theoretical resemblance between gravity and QCD, as well as phenomenological similarities between dark matter and hadronic physics. These parallels suggest that gravity's self-interaction may play an important role in dark matter phenomenology. I will then discuss experimental supports for this new approach.

The aim of the KArlsruhe TRItium Neutrino experiment KATRIN is the direct and model independent determination of the absolute neutrino mass scale down to 0.2 eV. For this purpose, the integral electron energy spectrum will be measured close to the endpoint of molecular tritium beta decay. The electrostatic retardation method with magnetic adiabatic collimation (MAC-E filter) combines high energy resolution with high statistics and small background. The various components of the experiment (gaseous tritium source, pumping-transport system, pre- and main spectrometer, detector and rear system) will be reviewed, together with various systematic effect and background issues. In addition, possibilities for light and keV sterile neutrino determinations will also be discussed.

The electromagnetic form factors of the proton are extracted by analyzing unpolarized and polarized electron scattering data assuming the Born approximation. The extracted ratios of electric to magnetic form factors (G_E/G_M) by the two methods show a significant discrepancy that increases with Q². One possible explanation for the observed discrepancy is the contribution from two-photon exchange (TPE) effects, which are not generally accounted for in the standard treatment of radiative corrections. Theoretical calculations estimating the magnitude of the TPE effect are highly model-dependent and limited experimental evidence for such effect exists. The ratio of positron-proton to electron-proton elastic scattering cross sections (R = ^{σ(e+ p)}/σ(e^- p)) provides a model-independent measurement of the TPE effect. One such measurement of R was performed by using a mixed electron-positron beam at Jefferson Lab Hall B. Both electrons and positrons were elastically scattered from a 30-cm-long liquid hydrogen target. The resulting scattered particles were detected in CLAS. The elastic events were then identified by using elastic scattering kinematics. The measurement covers a range of Q² < 2 GeV² and 0:1 < ε < 1. In the kinematics of the experiment, our results are consistent with the hadronic calculation of the TPE effect by Blunden, Melnitchouk, and Tjon. The details of the CLAS TPE experiment and the results will be discussed.

One of Jefferson Lab's original missions was to further our understanding of the short-distance structure of nuclei. In particular, to understand what happens when two or more nucleons within a nucleus have strongly overlapping wave-functions; a phenomena commonly referred to as short-range correlations (SRC). I will review recent, Q^2 > 1 [GeV/c]^2 and Bjorken x > 1, (e,e') and (e,e'pN) data that have been used to probe the short-distance structure of the nucleus. New results using a Helium-4 target, which were recently released for publication, will be discussed along with future plans after the energy upgrade of Jefferson Lab.

The quantity d₂, written as an x²-weighted moment of a linear combination of the spin structure functions g₁ and g₂, has the interpretation of being the average transverse Lorentz color force felt by a quark immediately following its interaction with a virtual photon in the deep inelastic scattering (DIS) process due to the remnant di-quark system. It has been calculated in different nucleon structure models and in lattice QCD, where it is seen to be small and negative for Q² > 4 GeV². The existing measurement for the matrix element d₂ on the neutron from the combined data of SLAC E155 and Jefferson Lab E99-117 at Q² = 5 GeV² disagrees with the lattice QCD calculation by almost two standard deviations. This discrepancy served as the motivation for the E06-014 experiment in Hall A of Jefferson Lab. Double-spin asymmetries and unpolarized cross sections were measured in the scattering of a longitudinally polarized electron beam of energies 4.74 and 5.89 GeV from a longitudinally and transversely polarized ³He target, covering the DIS and resonance regions characterized by 0:25 < x < 0:90 and 2 ≤ Q² ≤ 7 GeV². This allowed for the extraction of dⁿ₂ matrix element in two ⟨Q²⟩ bins of 3.21 and 4.32 GeV². Additionally, the virtual photon-nucleon asymmetry Aⁿ₁ was extracted, along with the evaluation of the polarized-to-unpolarized quark ratios Δu ⁄ u and Δd ⁄ d. The matrix element a₂ is also obtained from our g₁ data. We present the results of our measurements, which are compared to the world data and various theoretical models and lattice QCD calculations. Future plans to measure dⁿ₂ and Aⁿ₁ with the upgrade of Jefferson Lab will be discussed.

It has been suggested that the difficulties in the interpretation of the flux averaged double-differential neutrino-carbon cross section measured by the MiniBooNE collaboration may due to contributions arising from reaction mechanisms other than single-nucleon knockout. The analysis of the large body of inclusive electron scattering data may provide a clue to pin down the role of the relevant mechanisms in a variety of kinematical regimes, thus shedding light on some of the unresolved issues of neutrino-nucleus scattering. As an example, I will argue that it may help to reconcile the different values of the nucleon axial mass reported by the MiniBooNe and NOMAD Collaborations.

The unique advantages of using polarized ³He as neutron spin filters, such as broadband and wide angular acceptance of neutron beams, have made it widely used among neutron scattering communities. Here we report the current status of the polarized ³He development at the Oak Ridge National Laboratory (ORNL). Over the last several years, we have developed a robust polarized ³He program to meet the increasing needs of ³He based neutron spin filters at ORNL’s High Flux Isotope Reactor (HFIR) and Spallation Neutron Source (SNS). At ORNL, spin-exchange optical pumping is used to produce polarized ³He. Two optical pumping stations have been built in the lab to perform ex situ pumping of ³He. In order to solve the complications in data analysis brought by the ³He polarization relaxation in the ex situ pumping, we have constructed in situ pumping systems for several beamlines which has produced very high ³He polarization (76%) and the polarization has been maintained throughout the experiments. In addition, a novel polarized ³He filling station for the Hybrid Spectrometer (HYSPEC) at SNS is under development. We will present the preliminary test results of this system.

Radium, due to its simple atomic structure, heavy mass, and large nuclear deformation, is an exciting candidate for a CP violation search in the form of an atomic electric dipole moment (EDM). Since CP violation is expected to play an important role in beyond the standard model physics, such a search is a sensitive probe of new physics. An ongoing experiment at Argonne National Lab, which aims to measure the EDM of laser cooled and trapped radium-225 atoms, has made considerable progress in recent years. Here I report the control and preparation of such atoms as well as the first observation of nuclear precession in trapped radium atoms. Together with the application of an electric field, nuclear precession is the signal that will become the first measurement of radium's EDM.

Presently ongoing or planned neutrino long baseline experiments all use nuclear targets. Any extraction of neutrino properties from observables in such experiments thus has to deal with the in-medium production and the final state interactions of outgoing particles. Traditionally, this has been done with neutrino event generators. In this talk I will show that the widely used neutrino generators have not yet reached the degree of sophistication of the experimental equipment for neutrino experiments. I will disuss the essential nuclear physics input for neutrino generators: QE, many-body interactions, pion production through resonances and DIS. I will then illustrate how all of these processes affect the event characterization, energy reconstruction and the extraction of neutrino oscillation parameters, using results from the nuclear physics based transport code GiBUU.

To unambiguously identify baryon resonances the measurement of polarization observables is of large importance. With the Crystal Barrel/TAPS experiment, located at the ELSA accelerator facility in Bonn, Germany, polarization observables have been determined using a linearly polarized photon beam impinging on a liquid hydrogen target. In this talk an overview of these measurements will be given and new results on the polarization observables I^S and I^C will be presented for the reaction γp → pπ⁰π⁰. A comparison of the results with predictions of the Bonn-Gatchina-partial wave analysis shows that the data provide new constraints for the extraction of baryon resonances. In addition, invariant mass distributions and Dalitz plots, indicating cascade-decays via different excited states will be discussed.

The work was performed by the CBELSA/TAPS Collaboration at the Helmholtz-Institut fuer Strahlen- und Kernphysik (University of Bonn).

Precision measurements of neutron interactions at low energies and high intensities offer many avenues to search for physics beyond the Standard Model. Motivated by this particle physics impact, there are ongoing experimental programs which utilize cold and ultra-cold neutrons (UCN) to measure the neutron static electric dipole moment, neutron β-decay parameters, and possible new short range interactions. In this talk, we will focus on two such programs: a β-decay program at Los Alamos National Laboratory (LANL) utilizing UCNs and a proposed experiment to search for neutron-antineutron oscillations at Fermi National Accelerator Laboratory (FNAL). Modern studies of neutron β-decay offer an improved, nuclear structure independent determination of the CKM matrix element V_ud through more precise measurements of the neutron lifetime and β-decay correlation coefficients. V_ud is a critical input to a direct test of CKM matrix unitarity, which places stringent limits on extensions to the Standard Model for charged current interactions. This talk will begin with a summary of the UCNA experiment at LANL, the only experiment to perform a measurement of angular correlations in neutron β-decay (spin-electron asymmetry parameter A(E)) using UCN. We then present a recently proposed experiment to search for n − ‾n oscillations using free neutrons at FNAL, which would provide a sensitive window to probe for baryon number violating interactions with Δβ = 2, would provide insight into the origin of matter-antimatter asymmetry in the universe and would change our ideas on the energy scales relevant for quark-lepton unication and neutrino mass generation. Methods for an improved search for n − ‾n oscillations using free neutrons and recent detector characterization studies for such a search will be discussed.

In 1983 the Europeon Muon Collaboration (EMC) published their deep inelastic scattering ratios that showed that partons in heavy nuclei do not behave the same a partons in light nuclei. Over the decades, much work has been done by both experimentalists and theorists to understand why. In 2009, Jefferson Lab provided a new clue to the cause with their light nuclei EMC effect data. These new data pointed to the EMC effect being a local density effect instead of an average effect. Soon after this observation, a phenomenological link between nuclear short-range correlations and the EMC effect was made. This seminar will review both the EMC effect and short-range correlation results and the link that has been made between these two seemingly unrelated experiments.

The MUSE experiment aims to provide key missing information in the quest to resolve the proton radius puzzle: the difference between the 0.88 fm proton radius measured in atomic hydrogen and ep elastic scattering experiments and the 0.84 fm radius measured in muonic hydrogen. Over the last three years since the puzzle emerged, none of the many attempts to find a solution have reached a universally accepted resolution. Possible solutions include novel beyond standard model physics, novel hadronic physics and issues and/or underestimated uncertainties in the ep scattering data.

Recently there have been high precision electron scattering experiments at Mainz and JLab, and further measurements are planned. A series of excitation spectrum measurements on light nuclei are planned at PSI. The MUSE experiment will open up a new line of experimental investigations by measuring elastic muon scattering on the proton at the PSI piM1 beamline.

MUSE will scatter a mixed muon/pion/electron beam on a liquid hydrogen target with a Q^2 range of approximately 0.002 - 0.08 GeV2. Measurements of both μ+ and μ- at multiple beam momenta will enable checks of systematics, determination of two-photon exchange effects and magnetic contributions, and a radius determination at a similar level of precision to existing ep scattering experiments. Simultaneous electron scattering will allow similar tests and a direct comparison of the two probes, providing an excellent test of lepton universality. The physics background, status, and plans for the experiment will be discussed.

The proton spin-dependent structure function g2p in the resonance region has been measured in a recent experiment at Jefferson Lab in Hall A. A polarized electron beam of energy 1.157-3.349 GeV was incident on a transversely polarized NH₃ target. An inclusive measurement at 5.69 deg was performed in order to determine the g2p structure function in the Q² region of 0.02-0.20 GeV². No measurement of this quantity has been conducted at such a low-Q² range before. This experiment will allow us to test the Burkhardt-Cottingham sum rule at low Q² and extract the generalized longitudinal-transverse spin polarizability δ_LT. Chiral Perturbation Theory (χPT) is expected to work in this kinematic region and this measurement of δLT will give a benchmark test to χPT calculations. In this talk, I will give describe to the experiment and show the latest progress of the on-going analysis.

This talk will introduce the GDH Sum Rule for the deuteron and the technical hurdles involved in making a doubly polarized measurement via the photodisintegration process d(γ,n)p. Three experimental components, the Duke Free Electron Laser Laboratory, the frozen-spin target HiFrost, and the Blowfish detector array, will be discussed, as well as the motivation for measuring the GDH Sum Rule.

Using the CLAS detector at Jefferson Lab, double spin asymmetries (A||) for quasi-elastic electron scattering off the deuteron have been measured at several beam energies. The data were collected during the EG1 experiment, which scattered longitudinally polarized electrons with energies from 1.6 to 5.8 GeV off a longitudinally polarized cryogenic ND₃ target. The double spin asymmetries were measured as a function of photon virtuality Q² (0.13−3.17 (GeV/c)²), missing momentum (0.0−0.5 GeV/c), and the angle between the (inferred) “spectator” neutron and the momentum transfer direction (θ_nq). The results from EG1b are compared with a recent model that includes final state interactions using a complete parameterization of nucleon-nucleon scattering. I will discuss the results for the double spin asymmetry and compare them to this model as well as a simplified model using the plane wave impulse approximation.

Differential cross sections for exclusive π ‾ electro-production from the neutron in the reaction e+d → e′+π ‾+p+p_r have been measured over a broad kinematics range in the BoNuS experiment, where p_r is the recoil proton. The experiment was performed using a radial time projection chamber (RTPC) and the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab Hall B. The RTPC detector was specially built to detect low energy recoil protons and had a valid momentum acceptance from 67 to 250 MeV/c. The differential cross sections for D(e, e′π ‾p)p have been extracted, with the proton detected either by CLAS or by the RTPC. The structure functions σ_T + εσ_L, σ_LT and σ_TT were determined and will be presented in comparison with MAID and SAID predictions.

Phi meson photoproduction cross section in its neutral decay mode is measured for the reaction gamma p → p (KSKL). The experiment is performed with a tagged photon beam of energy 1.6 -3.6 GeV incident on a liquid hydrogen target of the CLAS at Thomas Jefferson National Accelerator Facility. The final state is identified via reconstruction of KS in the invariant mass of two oppositely charged pions and by requiring missing particle in the reaction gamma p → p KS X to be KL. Presented results significantly enlarge the existing data on phi meson photoproduction. These data, combined with the data from the charged decay mode, will help to constrain different mechanisms of the phi photoproduction.

The CLAS Collaboration is using the p(e, e'K⁺p)π⁻ reaction to perform a measurement of the induced polarization of the electroproduced Λ(1116). The parity-violating weak decay of the Λ into pπ⁻ (64%) allows extraction of the recoil polarization of the Λ. The present study uses the CEBAF Large Acceptance Spectrometer (CLAS) to detect the scattered electron, the kaon, and the decay proton. CLAS allows for a large kinematic acceptance in Q² (0.8 ≤ Q² ≤ 3.5 GeV²), W (1.6 ≤ W ≤ 3.0 GeV), as well as the kaon scattering angle. In this experiment a 5.499 GeV electron beam was incident upon an unpolarized liquid-hydrogen target. The goal is to map out the kinematic dependencies for this polarization observable to provide new constraints for theoretical models of the electromagnetic production of kaon-hyperon final states. Along with previously published photo- and electroproduction cross sections and polarization observables from CLAS, SAPHIR, and GRAAL, these data are needed in a coupled-channel analysis to identify previously unobserved s-channel resonances.

Recent theories of dark matter predict A’ gauge bosons in the mass range of 0.01-10 GeV that couple to charged fermions with a strength of α’/α_ΕΜ~ 10^-4 of the photon or less. The DarkLight (Detecting A Resonance Kinematically with eLectrons Incident on a Gaseous Hydrogen Target) experiment intends to use the 1 MW 100 MeV electron beam at the Jefferson Lab Free Electron Laser incident on a 10¹⁹ H₂/cm² thick target to study the process e^- + p -> e^- + p +e^- + e⁺. A dark force particle would show up as a narrow resonance in the radiated e⁺ - e^- system. DarkLight would explore the A’ mass region 10-100 MeV with sensitivity to couplings as low as a’/a_EM ~10^-7 with 1/ab of data.

Using principles analogous to those of conventional optics it is possible to construct fully electrostatic ion traps which act as a resonant cavity for ion beams. Such traps exhibit an unexpected phenomenon of self-bunching which allows for long lifetimes of trapped ion bunches.
I will present the principles and design of one such electrostatic trap, originally designed at the Weizmann Institute. I will further discuss the experimental possibilities afforded by such a trap, with emphasis on mass spectroscopy and possible measurements of β decay correlations of trapped radioactive ions. Such measurements allow the study of possible standard model extensions affecting the structure of the weak interaction.

Two phenomena have been observed recently in experiments with slow neutrons: quantum states of ultracold neutrons (UCN) in the Earth’s gravitational field [1] and quantum states of cold neutrons (CN) in the centrifugal potential in the vicinity of a curved mirror [2]. The first experiment presented the first observation of quantum states of matter in a gravitational field; the second one is also known as the neutron whispering gallery effect. They are related by common experimental methods used, by common mathematical description, but also by their applications in elementary particle physics, in quantum optics, in surface science [3]. It is curious that these experiments present the first direct demonstration of the weak equivalence principle for an object in a quantum state. Much more precise measurements of/with these phenomena are going to be performed in a recently constructed second-generation GRANIT spectrometer [4]. Analogous experiments could be probably performed in future with anti-matter atoms [5-6], with interesting applications in various domains of science.

1. V.V. Nesvizhevsky et al, Nature 415, 297 (2002); S. Baessler et al, J. Phys. G 36, 10 (2009).
2. V.V. Nesvizhevsky et al, Nature Phys. 6, 114 (2010).
3. V.V. Nesvizhevsky, Phys.-Uspekhi 53, 645 (2010).
4. S. Baessler et al, Compt. Rend. Phys. 12, 707 (2011)
5. A.Yu. Voronin et al, Phys. Rev. A 83, 032903 (2011).
6. A.Yu. Voronin et al, Phys. Rev. A 85, 014902 (2012).

A complete characterization of the spectrum of N and Delta resonances is essential to understand the internal structure of the nucleon. Although the Constituent Quark Models(CQM) gives good predictions for resonances in low-energy region(less than 1.8 GeV). For mass states above 1.8 GeV, many of them have not been found in experiment. This discrepancy between theory and experiment can be attributed to two reasons. One reason is that most identified resonances were discovered in piN scattering; thus, the states that couple weakly to this channel will not be seen. Another reason is that the resonances are both broad and overlapping, which make them hard to identify. The photon production of pseudoscalar mesons studied in the G14 experiment gives us a chance to look at the decay channels in pi-pi-N, eta-N, K-Lamda, etc. Moreover the use of polarized beam, polarized targets, and the detection of the polarized recoil nucleon allow us to measure a large number of polarization observables. These observables will help removing the ambiguities in determining the multipoles in partial wave analysis for the identification of the undiscovered nucleon resonances.

I will discuss applications of perturbative QCD to the study of inclusive processes that are sensitive to the intrinsic transverse motion of bound state constituents of hadrons. Transverse momentum dependent (TMD) factorization is the theoretical framework that is needed to address these processes in perturbation theory.
Factorization refers to the separation of short-distance (hard) physics, which is calculable in perturbative QCD, from the large-distance non-perturbative effects inside the transverse momentum dependent parton distribution and fragmentation functions.
I will summarize recent theoretical developments in TMD-factorization, and discuss current efforts to apply TMD-factorization phenomenologically to extract information about hadron structure.

A measurement of a non-zero electric dipole moment of the neutron would have implications on our understanding of the Standard Model and the matter-antimatter asymmetry in the present universe. In 1994 Golub and Lamoreaux (Physics Reports 237, 1—62 (1994)) proposed a new measurement strategy that makes use of several unusual properties of liquid helium. A collaboration of 19 US research groups is now pursuing R&D for an experiment to be installed at the Spallation Neutron Source at ORNL. The talk will outline the features and significance of this measurement, and then focus on the cryogenic challenges of the experiment.

Generalized Parton Distributions (GPDs) in Deeply Virtual Compton Scattering (DVCS) have been widely recognized and used as a useful tool to explore the quark and gluon structure of the target hadrons. However, we recently pointed out treacherous kinematic issue in analyzing DVCS in terms of GPDs. In this talk, we present our key findings in the simplest possible level of complete amplitude including the lepton current. Implication in the Jefferson Lab experiment of DVCS will also be discussed.

Among the most exciting discoveries about the Quark-Gluon Plasma State is its extraordinary opacity to color-charged objects (quarks and gluons). This property, while facilitating rapid equilibration of the plasma, hides the state at the earliest times from direct measurement. Colorless probes (direct real and virtual photons) provide access to the earliest time scales, but suffer from huge backgrounds of electromagnetic decays of light mesons. In this seminar, we'll explore how the mass of virtual photons can be used to reduce background from light mesons and provide access to the direct plasma "shine" from the earliest times.

The availability of polarized proton beams at RHIC opened a window to an unexplored kinematic region up to a center of mass energy of 500 GeV for elastic and diffractive proton-proton scattering. Besides the measurement of the total scattering cross section, the polarization of the protons leads to a single spin asymmetry $A_N$, arising from an interference between the electromagnetic proton spin-flip and the hadronic non-flip scattering amplitudes. The measurement is sensitive enough to detect a possible hadronic spin-flip contribution, which cannot be ruled out by the available data. Detailed theoretical model calculations are also available for the double spin asymmetries $A_{NN}$ and $A_{SS}$, assuming varying magnitudes of an Odderon contribution to the scattering amplitude, which we will be able to distinguish at the 5\% level. The Odderon is the hypothetical charge and parity odd partner of the dominant Pomeron. Preliminary data from RHIC run 09 taken with the STAR detector will be shown.

A non-zero value of the neutron electric dipole moment (nedm) would represent a violation of T reversal and would be strong evidence for new physics beyond the standard model. After presenting an overview of the project and the experimental methods that are being designed into the search for a neutron edm that is foreseen to be carried out at the Oak Ridge Spallation neutron source (SNS) we discuss a newly discovered systematic error and efforts to deal with it.

The GRAAL experiment was located at the European Synchrotron Radiation Facility (ESRF) in Grenoble (France). It consisted of a Compton backscattered polarized photon beam, of 1.5 GeV maximum energy, and a large solid angle detector (LAGRANgE), optimized for neutral particle detection. Over more than ten years of activity has provided photon beam asymmetry measurements of pseudo-scalar meson photo-production reactions on both proton and neutron targets, providing strong constraints to models that allow for the extraction of nucleon resonances properties from experimental results. Highlights from published data are summarized and the latest results on omega meson photo-production are presented

In 2-D Mammography, breast tissues are superimposed in single projection image thereby possibly masking small cancer. X-ray breast tomosynthesis (XBT) is a technique for reducing this problem by providing a 3-D image. However, it still provides only anatomic (structural) information. Since cancerous and harmless breast masses (lesions) often have similar structures, distinguishing them using structural imaging alone is difficult. The task of distinguishing between benign and malignant breast lesions can be significantly aided by taking advantage of the differences in their biological (functional) characteristics. Molecular breast imaging (MBI) is a recent technique that uses intravenously injected compounds (tracers) that are taken up to a much greater degree by malignant lesions than benign ones. By attaching a radioisotope atom to these tracer molecules they can give off a signal that can be detected by specially designed cameras placed near the breast. These cameras permit functional imaging of the entire breast and have resulted in reliable detection of tumors less than 1 cm in size. Nevertheless, similar to Mammography, the 2-D nature of MBI prevents any depth information of lesions from being obtainable. Moreover, the correction for gamma signal attenuation through the breast is virtually impossible in MBI. Our group is developing a unique dual modality tomographic (DMT) breast scanner that combines x-ray tomosynthesis and 3-D MBI tomosynthesis (MBIT) on a single integrated gantry. This talk will focus on the functional part. Specifically, image acquisition, reconstruction and restoration in MBIT will be covered.

Hydrodynamics is the universal theory describing the behavior of fluids when their spacetime variation is on scales longer than any microphysical scale in the fluid. Relativistic hydro has applications in heavy ion collisions and early Universe cosmology, and has seen a surge of interest due to heavy ion experiments and theoretical developments in AdS/CFT. I will explain what second order hydrodynamics is and why it is the minimum theory to study in the relativistic case. Then I discuss some limitations of the theory, including a new bound on how small the viscosity can be and a complication in the rigorous definition of the viscous relaxation time τ_π.

The bare mass of the three valance quarks only makes up ~ 1% of the proton mass, the rest is a sea of gluons, quarks and anti-quarks, which is dominated by the up, down and strange quarks. From the quark model, one might naively expect that the electromagnetic form factors are determined only by the valence quarks, with no contribution from the strange sea quarks. But, existing data suggesting a non-zero strange quark contribution to these form factors at high Q² has been a topic of great interest. A new measurement of the strange quark vector form factors by the HAPPEX III collaboration is discussed.

The elastic electromagnetic form factors of the nucleon are among the most important observables characterizing its structure. Accurate knowledge of the proton form factors at large momentum transfers is required to test predictions of perturbative QCD, to constrain the nucleon Generalized Parton Distributions (GPDs), and to determine the nucleon's model-independent transverse charge and magnetization densities at small impact parameters. Through their relationship to GPDs, the nucleon form factors are also relevant to the nucleon spin puzzle, helping to evaluate Ji's angular momentum sum rule. In this seminar, I will present and discuss the results of recent recoil polarization measurements of the proton electric-to-magnetic form factor ratio. These results extend the momentum transfer reach of the method to Q2=8.5 GeV2, an increase of more than 50%. Additionally, our precise measurements at Q2=2.5 GeV2 will constrain models of multi-photon exchange effects believed responsible for the discrepancy between the Rosenbluth and polarization experiments.

One of the longstanding unsolved problem in the nuclear physics is that of the nucleon resonances N* and Δ*. The lifetime of these intermediate states is very short since they decay strongly. Their parameters, mass, width, and coupling constants to various decay modes are not well known. To solve this problem, double polarization experiments are considered to be a very effective tool. I will present the preliminary result of the helicity asymmetry “E” for γp → π ⁰ p channel from the first double polarization experiment at Jefferson Lab and compare this result with the prediction of theoretical models.

The quest for an understanding of the internal dynamics of the most fundamental systems in nature, the Hadron, continues. The theory of Quantum Chromodynamics, developed to describe these systems, explains many of the interactions which occur in the Hadron. This theory however cannot presently be solved analytically in the low-energy regime, the realm of non-perturbative QCD. Therefore in the place of these solutions, models of the baryon are used which treat the baryon as a system of three constituent quarks. These models however predict an excited baryon spectrum that has a higher density of states than that which has been observed experimentally. This is the so-called “missing resonance” problem. With the ultimate goal of finding evidence for the existence (or non-existence) of these resonances, quantities called “polarization observables” can be measured. These quantities which occur when the constraint of polarization is imposed on the reactions are highly sensitive to resonance production. In recent years, both single- and double-polarization experiments have been carried out at Jefferson Lab in Newport News, Virginia with the goal of resolving this missing resonance problem. One such polarized photoproduction experiment used linearly polarized photons incident on an unpolarized LH2 target. The analysis of a double meson final state from this polarized photoproduction data utilizing the power of a kinematic fitter has the ability to make highly accurate measurements of these observables. The analysis of γ p → p π ⁺ π ^- reactions and the extraction of two such observables, Is and Ic, is discussed.

All personnel who might want to use radioactive sources or other radioactive material, or want to work in areas where such materials are used, are required to obtain certification from the Office of Environmental Health and Safety. Deborah and Greg will present the required Radiation Safety Training Course leading to this certification. Anyone who may want to use radioactive material or work in an area where such material is used should attend this course.

The equivalence principle (EP) states that in a uniform gravitational field all bodies fall with the same acceleration regardless of their mass and internal structure. The equivalence principle is the underlying foundation of General Relativity, our current theory of gravity. Despite the fact that General Relativity has passed many precision experimental tests, it is fundamentally incompatible with the quantum nature of the standard model. Modern theories, like string theory and quantum gravity, predict violations of the equivalence principle. In the experiments conducted at the University of Washington a composition dipole is suspended from a thin fiber in a vacuum vessel that rotates with constant rate. A violation of the equivalence principle would yield to a differential acceleration of the two materials to a source mass located to the side of this torsion balance. Any differential acceleration can be detected as a sinusoidal excursion of the torsion pendulum at the rotation period. In this talk I will present measurements of the differential acceleration with an uncertainty of 3 fm/s2. These measurements set new limits on equivalence principle violating interactions between the composition dipole and a variety of sources.

Double spin asymmetries for the proton and the deuteron have been measured in the EG1b experiment using the CLAS detector at Jefferson Lab. Longitudinally polarized electrons at energies 1.6, 2.5, 4.2 and 5.7 GeV were scattered from longitudinally polarized NH ₃ and ND ₃ targets. The double spin asymmetry Ak has been extracted from these data as a function of Q ² and W with unprecedented precision. The virtual photon asymmetry A ₁ and the spin structure function g ₁ can be calculated from these measurements by using parameterizations to the world data for the virtual photon asymmetry A ₂ and the unpolarized structure functions F ₁ and R. The large kinematic coverage of the experiment (0.05 GeV ² < Q ² < 5.0 GeV ² and 1.08 GeV < W < 3.0 GeV) helps us to better understand the spin structure of the nucleon, especially in the transition region between hadronic and quark-gluon degrees of freedom. The results from EG1b combined with other experiments provide a good description of the virtual photon asymmetries making their parameterizations possible in a large kinematic range. In this talk, the results on A ₁ , g ₁ and the first moment Γ ¹ ₁ of the deuteron will be presented. The parametrization efforts on the asymmetries and the spin structure functions will be discussed. The neutron spin structure function, extracted from the combined proton and deuteron data, will be shown.

The NPDGamma experiment aims to measure the correlation between the neutron spin and the direction of the emitted photon in neutron-proton capture. A parity violating asymmetry from this process can be directly related to the strength of the hadronic weak interaction between nucleons. The first phase of the experiment was completed in 2006 at LANSCE. The methodology will be discussed and preliminary results will be presented. The next run will start in early 2010 at the SNS at ORNL with several improvements, which will be discussed. The upcoming run will yield a measurement with a projected statistical error 1x10 ^-8 . This will allow the results to be compared meaningfully with theoretical predictions

The GDH sum rule connects ground state properties of the nucleon with helicity-dependent cross sections. To investigate these cross sections on the deuteron, experiments have been carried out by the A2-Collaboration at the Mainz Microtron (Germany) in 1998 and in 2003, using circularly polarized photons on a polarized d-butanol target. The latest analysis results and the status of the GDH experiment with the Crystal Ball detector are reported.

This is the only Jefferson Lab polarized 3He experiment which is seeking to better understand the 3He system, as opposed to using it as an effective neutron target, by measuring double-polarized asymmetries in the 3He(e,e'd) reaction which are believed to be a probe particularly sensitive to the details of the 3He system. Major theoretical advances have been made in the Faddeev calculations of the Bochum/Krakow and Hannover groups, resulting in quite distinct descriptions of these observables. This development has important implications for experiments using 3He as an effective neutron target.

An observation of neutrinoless double beta decay would have significant impact on our understanding of the lepton sector of the Standard Model. First, neutrinoless double beta decay could shed light on the absolute mass scale of the neutrino mass spectrum, a quantity which cannot be constrained by neutrino oscillation experiments. Second, double beta decay is only allowed if the neutrino and anti-neutrino are identical which is a basic prediction of many extensions of the Standard Model including many grand unified theories. The Enriched Xenon Observatory (EXO) is developing sensitive searches of double beta decay using Xenon-136. The first phase of the experiment, called EXO-200, is in the final stages of assembly in the WIPP underground facility in Carlsbad, NM and will be by far the largest double beta decay experiment ever attempted. The current status of the EXO-200 experiment will be presented.

First-principles calculations of the nucleon form factors and generalized form factors have been made possible by employing the lattice QCD techniques. Together with the experimental efforts, lattice results for the nucleon form factors have deepened our understanding of the internal structure of the nucleon, such as the charge and current distributions, and the spin decomposition of the nucleon. In this talk, I will present some recent lattice QCD results for the nucleon form factors using a five-dimensional chirally symmetric fermion action. I will also address some challenges faced by modern lattice form factor calculations.

The muon group at Illinois is performing three experiments at the Paul Scherrer Institute all measuring the muon lifetime with high precision. The MuLan experiment uses a simple soccer-ball like scintillator array to detect the decay positrons. We collected twice 10 ¹² muon decays in two different target materials to obtain the final precision of 1 ppm which will give a 20 times better determination of the Fermi constant G _F . A first result was recently published [1] which already improved the precision of G _F to 5 ppm. The muon capture experiment MuCap uses a negative muon beam stopped in a time projection chamber as an active target filled with ultra-pure hydrogen gas. The elementary capture process μ ^- +p → n+ ν offers a rare (0.15%) but additional disappearance channel. The measured difference of the positive and negative muon's lifetime determines the rate of the capture process to a final precision of 1%. This can be used to derive an improved value of the proton's pseudoscalar form factor g _P to 7% precision. A first result gP = 7.3  1.1 has been published [2]. This is a first precise, unambigous determintation of gP and an important test of QCD symmetries. Recently, we started a new experiment, MuSun [3], that will start a first commissioning run at the end of 2008. Here, a measurement of the μ ^- +d → n+n+ ν provides a benchmark of the understanding of weak processes in the two nucleon-system. It was shown, that other weak reactions involving the two nucleon system (pp → de ⁺ ν or ν +d reactions) are related to the same low-energy constant, characterizing the two nucleon system at short distances. This constant is not well constrained and therefore the MuSun experiment comes closest to calibrating these basic astrophysical reactions under terrestrial conditions. [1] Phys. Rev. Lett. 99, 032001 (2007) [2] Phys. Rev. Lett. 99, 032002 (2007) [3] http://www.npl.uiuc.edu/exp/musun/documents/prop07.pdf

The talk presents an overview and status report of the MEG experiment at PSI, Switzerland, which searches for the decay Mu -> e Gamma at the 10^(-13) level. The motivation for the experiment is discussed and compared with other Lepton Flavor Violating processes, such as Mu A -> eA conversion. To accommodate the extremely high demands regarding pile-up suppression, timing resolution, and versatility, a special waveform digitizing technique was designed and implemented in the MEG experiment. It relies on the Domino Ring Sampling chip (DRS), capable of digitizing 8 channels with 5 GHz and 12 bits effective resolution on a single radiation hard CMOS chip. The DRS chip is currently used in the MEG experiment to digitize 2000 drift chamber channels and 1000 photomultiplier channels, eliminating the need for traditional ADCs and TDCs. Techniques used in MEG for waveform processing (e.g., data compression, pulse shape discrimination, and crosstalk elimination) may have applications in other rare decay experiments, and in cosmic ray astronomy.

A new generation of ultra-precise measurements of parity-violation (PV) effects in electron scattering at 12 GeV at JLab is being currently developed. These experiments will require an improvement in beam polarimetry accuracy, by a factor of 2 to 3 in comparison with the present most accurate measurements. I will present an outline of the planned PV experiments, describe the existing polarimetry methods, and discuss a proposal to improve considerably the accuracy of polarimetry based on Moller scattering. It is proposed to use polarized atomic hydrogen gas, stored in an ultra-cold magnetic trap, as the polarimeter target. Such a target of practically 100% polarized electrons could provide a systematic accuracy better than 0.5%. Although such traps have been built for particle physics applications, the storage cell has not been used so far as the target in a high power beam. Possible impacts the CEBAF beam can make on such a target will be discussed, including heating by ionization losses and the impact of the beam electromagnetic (RF) radiation.

Using a novel 4π detector the Nab collaboration intends to measure a, the electron-neutrino correlation parameter, and b, the Fierz interference term, in neutron beta decay. The Nab experiment will be conducted in the Fundamental Neutron Physics Beamline at the Spallation Neutron Source in Oak Ridge, TN. I will present the design and simulation of the Electro-Magnetic Spectrometer which will be used to confine the decay products and shepherd them to the detector.

The PEN experiment aims to measure the semileptonic decay π → eν(γ)(π_e2 decay) branching ratio at PSI, with an ncertainty of ΔB/B∼5×10^-4,or better, using a large-angle detector system featuring a pure CsI calorimeter. This experiment will give a stringent test of lepton universality. Preliminary results from a basic level analysis of data from the first two developmental runs will be discussed. These results, coupled with a discussion of experimental techniques, such as the use of a segmented active degrader and target waveform digitization, will demonstrate our ability to control systematic uncertainties in the experiment.

The impact of very precise CLAS and COMPASS g ₁ /F ₁ data on the polarized parton densities and higher twist effects is discussed. It is demonstrated that the inclusion of the low Q ² CLAS data in the NLO QCD analysis of the world DIS data improves essentially our knowledge of HT corrections to g ₁ and does not affect the central values of PDFs, while the large Q ² COMPASS data influence mainly the strange quark and gluon polarizations, but practically do not change the HT corrections. The uncertainties in the determination of polarized parton densities are significantly reduced due to both of the data sets. These results strongly support the QCD framework, in which the leading twist NLO pQCD contribution is supplemented by higher twist terms of O(Λ ² /Q ² ). Different solutions for the polarized gluon density, as well as the present status of the proton sum rule are also discussed.

Large branching fractions for hadronic B decays involving the eta^prime (1997) and also in the B semileptonic decay to the eta^prime (2006) could potentially be caused by the extra 2-gluon couplings from the singlet component of the eta^prime meson. Now, for CLEO-C, we look to semileptonic decays of the D meson to the eta^prime to see if there is evidence for enhancement there as well. We make improvements to the “neutrino reconstruction” method used to study B decays, and find that the new algorithm can also be used to simultaneously measure a large number of D hadronic decays as well.

The Spin Asymmetry on the Nucleon Experiment (SANE) will employ a revolutionary increase in Figure of Merit to obtain precise gp2 and Ap1 results at high Bjorken x. Using the highest available JLab beam energy, a 194 msr electromagnetic calorimeter will view the UVa polarized NH3 target at 8.5 times 10^34 proton luminosity. The large Bjorken x region provides an important view on proton structure where the sea quarks have been stripped away. Using measurements of these ``naked protons'' is crucial for the understanding of strong QCD and can provide a connection between experimentally measured moments of polarized structure functions and quark matrix elements calculated in lattice QCD. The experiment is scheduled to begin installation in June, and will begin taking data in October, using JLab's 5.9 GeV polarized electron beam. We will discuss the physics motivation for SANE, as well as the current status of the preparations and expected results.

A Hybrid ³ He Polarizer is being constructed for use by the Center for InVivo Hyperpolarized Gas MR Imaging at the University of Virginia Health System. It will take advantage of the Hybrid Spin Exchange Optical Pumping, and it will be calibrated using a combination of Adiabatic Fast Passage NMR and Electron Paramagnetic Resonance. These techniques will be detailed, and the construction progress will be summarized.

Hybrid spin exchange optical pumping consistently outperforms pure alkali SEOP. Hybrid cells contain an alloy of potassium and a small amount of rubidium, whereas conventional cells contain a single species of metal, typically Rb. K-3He spin exchange is more efficient than Rb-3He. Consequently, less laser power is required to achieve a higher noble gas polarization with the benefit of a shorter polarization time. The hybrid technique has been successfully employed in the large scale production of target cells for use in nuclear physics experiments and shows great potential for use in medical imaging. The production of hybrid alloys, optimization, and results will be discussed.

The Low Energy Neutron Source at Indiana University is a University-based long-pulsed source that makes use of a coupled solid methane moderator operating at temperatures below 10K. I will present recent results in which the moderator performance is compared to the predictions from our recently developed model for methane dynamics in the low temperature (Phase II). I will also present the UCN production in solid oxygen involving magnon (spin wave) exchanges which is fundamentally different from the well-known phonon mechanism in solid deuterium.

The extrapolation of nucleon magnetic form factors calculated within lattice QCD is investigated within a framework based upon heavy baryon chiral effective-field theory. All one-loop graphs are considered at arbitrary momentum transfer and all octet and decuplet baryons are included in the intermediate states. Finite range regularisation is applied to improve the convergence in the quark-mass expansion. The resulting values of the form factors at the physical pion mass are in good agreement with the experimental data.

I will give an introduction to the pentaquarks, possible five quark baryons. Quantum Chromodynamics does not forbid existence of such a states, however experimental evidence for their existence is controversial. The whole sitation becomes even more complicated recently as some experiments claiming the discovery of pentaquarks did not see it in a repeated high statistics data set and therefore set up an upper limits for the cross section for the production of the Theta+ baryon on the order of a few nano barn. I will discuss this and also the possibility on how one can increase the sensitivity of the measurement using Quantum Mechanical interference with other strong production channels leading to the same final state.

The question after the individual parton (quarks and gluons) contributions to the spin of the nucleon is even after 20 years of experimental efforts not yet solved. After several very precise measurements in polarized deep inelastic scattering it is clear, that the spin of the nucleon can not be explained by the contribution of the quarks alone. This is affirmed by the newest results from COMPASS, HERMES and JLAB on the inclusive spin structure function g1 and on the individual contributions from the different quark flavors from semi-inclusive deep inelastic scattering data. Recently COMPASS and HERMES have started to measure the gluon polarization by isolating the photon gluon fusion process in semi-inclusive deep inelastic scattering; latest results on the contribution of the gluons to the nucleon spin from these measurements and RHIC will be discussed. The clear experimental evidence of exclusive reactions, especially DVCS, allows in the formalism of generalised parton distributions the study of an other component of the nucleon spin the orbital angular momentum. The most recent results on indications of the size of the orbital angular momentum of quarks will be presented.

In 2003 new experimental evidence was presented for the observation of the exotic baryon Θ ⁺ (1540) with a minimal quark content $uuddar{s}$. Quickly more than ten nuclear and high energy physics experiments reported positive results, apparently confirming the existence of the Θ ⁺ (1540), but all suffered from low statistical precision. An increasing number of null results started to appear, seemingly in contradiction with the positive sightings. Now the null results dominate the positive results, often with impressive statistical precision, and cast doubt on the existence of the Θ ⁺ (1540). The experimental status will be discussed, including some recent positive results. The past contributions and ongoing efforts of the Hermes experiment will be highlighted.

The pion charge form factor, F _π , is the fundamental interest in the study of the quark-gluon structure of hadrons. The relatively simple < qq > valence structure makes the pion an ideal test case for all models of hadronic structure. Experimentally, the measurement of the pion form factor poses special challenges. The technique utilizes a precision Rosenbluth seperation of the p(e,e' π ⁺ )n reaction at low -t. F _π is then extracted from the separated σ _L cross sections with the aid of a model. Over the past several years, we have carried out two experiments at Jefferson Lab (JLab) to measure F _π over a kinematic range of Q ² = 0.6-2.45 GeV ² . These measurements are planned to be extended to higher Q ² with the completion of the JLab 12 GeV upgrade. These data would challenge QCD based calculations in the most rigorous manner. The recent JLab results will be presented and compared to a variety of model calculations, and the future outlook will be discussed.

Although Quantum Chromodynamics (QCD) is the acclaimed theory of the strong interactions, important longstanding questions still remain to be answered on the nature of confinement of quarks and gluons inside the proton, and on their dynamical contribution to the proton's mass and spin. Deeply Virtual Compton Scattering (DVCS) and Exclusive Meson Production provide alternative tools to purely inclusive reactions that have significantly improved our studies of hadronic structure. By allowing for an additional momentum transfer "t" to the proton besides the large momentum transfered in the deep inelastic collision, one can in principle simultaneously access the longitudinal momentum fraction of the quarks and their position inside the proton, providing 3D "images" of quarks in hadrons. The price one pays for the rich phenomenology accessible through DVCS is a dramatic increase in complexity, due to the enlarged phase space one needs to cover. A new approach is being developed based on Self-Organizing Maps (SOMs), broadly related to Neural Networks, that allows for extensive parameter searches and enables the user to directly control the data selection procedure. Finally, among a wide range of recently studied implications, the SOMs models are connected to complexity theory, leading to the possibility of studying emergent behaviors in the system's properties.

Experiment E04-007, in Hall A at Jefferson Lab, is a high precision measurement of the reaction P(e,e'P)π ⁰ from the threshold to 20MeV above, and Q ² values between 0.04(GeV/c) ² and 0.14(GeV/c) ² . The near threshold cross sections are relatively small, which demand high resolution and as large acceptance as possible. Hall A, with the HRS and large acceptance BigBite spectrometer satisfies these requirements. I will talk about BigBite spectrometer, and also explain how the results of this experiment will provide a stringent test of chiral QCD.

Hyperpolarized ³ He diffusion MRI is a powerful tool to probe lung microstructure at a length scale inaccessible by conventional k-space MRI. For short diffusion times, ∆, time dependent diffusion measurements are sensitive to the surface to volume ratio (S/V) of the surrounding structure. Because of the high gas diffusivity (D _Xe =0.14cm ² /s, D _He =0.88cm ² /s) and the small size of alveoli (~200μm), measurement of S/V with the traditional single bipolar diffusion technique is challenging in the lung, since only small diffusion attenuation can be imparted within the short time scale regime (~200μs). Given the significance of short time scale diffusion in the assessment of lung microstructure, we developed a new technique that proves promising to enable such measurements.

Precision measurements in neutron decay allow to determine the coupling constants of weak interaction and to test aspects of the Standard Model of Elementary Particle Physics. This is achieved in measurements of the lifetime of the neutron and of several angular correlations in the decay. In my talk I will mainly report about the experiences and results we gained with the spectrometers PERKEO and aSPECT.

The EG4 experiment at the Jefferson Lab (E12-06-109) studied the GDH (Gerasimov-Drell_Hearn) Sum Rule that relates the difference of the two photoabsorption cross-sections to the anomalous magnetic moment of the proton, deuteron and neutron in the real photon limit. In reality we try to approach the real photon limit by having the Q ² very small. The experiment used a highly polarized electron beam and longitudinally polarized solid ammonia targets. The analysis to determine the deuteron target polarization using the data acquired from the NMR system will be shown with different analysis methods compared and further target polarization analysis via the scattering asymmetry method is also discussed.

Lattice QCD is a numerical method for solving the complicated dynamics of QCD in the non-perturbative, low energy regime, allowing computations of the spectrum and strong interactions of hadrons. To investigate the interactions of these hadrons with the remainder of the Standard Model (leptons and the electro-weak gauge bosons) and physics beyond the Standard Model, external operators must be included. This can be done by calculating hadron matrix elements with explicit operator insertions and generally also using external field techniques. In this second approach, the properties of hadrons are computed in an appropriate classical background field (e.g., electroweak) and their modification from the zero external field case determines the quantity of interest. I will discuss the advantages and disadvantages of this approach giving examples including the electromagnetic and spin polarisabilities of hadrons and the nuclear modification of parton distributions (the EMC effect).

Over 20 years ago Diakanov and Petrov suggested that the chiral phase transition in QCD might be similar to a metal-insulator transition based on the instanton description of the QCD vacuum. The arguments, however, are general and can be applied to other topological objects as well. I will review the proposed connection between QCD and a disordered medium and present some recent results from lattice QCD that are consistent with a localization transition in the lowest eigenmodes of the Dirac operator.

The gauge/string holographic duality has opened a new window into the non-perturbative regime of gauge theories. I will present the construction of supergravity duals to N=2 supersymmetric gauge theories coupled with matter (quarks) in the fundamental representation of the gauge group. The supergravity solutions are obtained by taking the decoupling limit of D3/D7 (color/flavor) brane systems. The backreaction of the flavor branes needs to be accounted for, as it allows to go beyond the quenched approximation on the dual gauge theory side. I will give the spectrum of mesons (bound states of quark-anti quark pairs) and discuss the effect of the backreacted flavor. Lastly, I will present the supergravity dual to the finite temperature gauge theory. This corresponds to a backreacted non-extremal D3/D7 system. At finite temperature, the fundamental matter undergoes a first order phase transition. I will discuss this phase transition from the perspective of the supergravity dual.

I will discuss the calculation of the Kaon B-parameter, a measure of indirect CP-violation in the Standard Model, using Lattice QCD. In particular, I will talk about the use of the Domain Wall Fermion formulation of Lattice QCD, a formulation which has continuum-like symmetry properties at finite lattice spacing at the expense of the introduction of an additional, fifth, dimension.

The Standard Model has been enormously successful at predicting the outcomes of experiments in nuclear and particle physics. The search for new physical phenomena and a fundamental description of nature which goes beyond the Standard Model is driven by two complementary experimental strategies. The first is to build increasingly energetic colliders, such as the Large Hadron Collider (LHC) at CERN, which aim to excite matter into a new form. The second, more subtle approach, is to do precision measurements at moderate energies, where an observed discrepancy with the Standard Model will reveal the signature of these new forms of matter. Here we demonstrate that the latest measurements of the electroweak force severely constrain the possibility of physics beyond the Standard Model to above the TeV energy scale.

The ratio of the electric to magnetic proton form factors has traditionally been determined using the Rosenbluth separation method, in which the ratio is extracted from the angular dependence of the cross section at fixed momentum transfer Q ² . Measurements at JLab using the alternative, polarization transfer technique found a dramatically different behavior of the ratio compared with the Rosenbluth results. I discuss the resolution of this discrepancy by considering the effects of two-photon exchange in elastic e-p scattering, taking particular account of the nucleon's finite size. Contributions from excited nucleon intermediate states are also considered, and estimates given of two-photon exchange corrections to the form factors of the neutron and He-3.

We present results from a comprehensive partial-wave analysis of pi+-p elastic scattering and charge-exchange data, covering the region from threshold to 2.6 GeV in the lab pion kinetic energy, employing a coupled-channel formalism to simultaneously fit pi-p-->eta n data to 0.8 GeV. Our main result, solution SP06, utilizes a complete set of forward and fixed-t dispersion relation constraints applied to the piN elastic amplitude. The results of these analyses are compared with previous solutions in terms of their resonance spectra and preferred values for couplings and low-energy parameters. Details are available at nucl-th/0605082

This talk will describe how to make intense identical positron and electron beams at Jefferson Lab and use them to measure two-photon exchange contributions to elastic electron-proton scattering. It will cover the results of a recent test run in CLAS where we produced about 10 pA each of electrons and positrons. The proton electric form factor describes the charge distribution of the proton. This has been measured extensively with electron scattering using Rosenbluth separations and polarization measurements. These measurements of the proton electric form factor disagree by a factor of three at Q ² = 6 GeV ² . Since alpha, the fine structure constant, is less than 1%, electron-proton scattering should be almost exclusively one-photon exchange. However, a two-photon exchange contribution of about 5% could explain the discrepancy between the measurements. We will determine the two-photon exchange contribution by measuring the ratio of the electron-proton and positron-proton elastic scattering cross sections to 1%.

A precision measurement of the electric form factor of the neutron, G _E ⁿ , has been carried out in Jefferson Lab's Hall A for Q ² values of 1.2 to 3.5 (GeV/c) ² using a highly polarized ³ He target and the quasi-elastic semi-exclusive ³ He(e,e'n) reaction. The experiment detected the ejected neutron with an array of scintillators and the scattered electron with the newly commissioned BigBite spectrometer. This new spectrometer has a large angular acceptance (80 msr), complementing the existing 6 msr high-resolution spectrometers, and enables a new generation of low-rate experiments with lower resolution requirements. A package of three multi-wire drift chambers was constructed in order to allow the spectrometer to operate under high rate conditions and achieve a spatial resolution of ~ 200 μm. The present status of the experiment will be presented as well as online results showing chamber performance at raw hit rates up to 20 MHz per plane.

I will make short introduction to clarify some notations used in N ^* physics and to present resonances which we have investigated within N ^* program of Hall B (JLab). Then I will discuss goals of N ^* program related to the Q ² evolution of &gamma ^* N &rarr N ^* amplitudes. Here the focus will be on the investigation of the scale of transition from nonperturbative to perturbative regime of QCD and on the nature of the Roper resonance. Further, I will discuss approaches used for the extraction of resonance contributions to the pion electroproduction and present the results obtained from JLab (mostly Hall B) data. This will be followed by the discussion of the obtained results and conclusion.

The search for a non-zero neutron EDM is a direct search for time reversal symmetry violation. Recently, a new experiment has been proposed to search for the neutron electric dipole moment (nEDM) with about two orders of magnitude improved sensitivity compared to the current experimental limit. One of the critical new ideas, which helps achieve the improved sensitivity, is the use of polarized Helium-3 as a co-magnetometer. Polarized He-3 is a key new component of this proposed experiment and thus maintaining its polarization under the true experimental conditions is essential for the success of the experiment. Following an overview of the past searches for the neutron EDM, I will describe the new experiment and the effort underway at Duke to study the relaxation of polarized He-3 under the conditions of the new proposed experiment.

The Hall C facility at Jefferson Lab is carrying out an extensive program of studies on nucleon spin physics, taking advantage of the CEBAF polarized electron beam and the versatile UVa polarized target. The program started in 2002 with a measurement of the longitudinal and transverse spin structure of the nucleon resonances in experiment 01-006 (Resonances Spin Structure - RSS) on proton and deuteron targets. This work is nearing publication of the final results for the proton, which will be presented. Preliminary results for the deuteron are available, too. The Spin Asymmetries on the Nucleon Experiment - SANE (E-03-109) is in preparation to extend the measurements of RSS and other experiments on the proton to higher momentum transfers. Going beyond inclusive polarized scattering, the Semi-SANE experiment (E-04-113) will detect scattered electrons and hadrons in coincidence, to determine the decomposition of the nucleon spin into its quark flavor components. Both SANE and Semi-SANE are scheduled to take data in 2008."

High energy limit of QCD is the area of major theoretical interest. One of its prediction is the so called perturbative BFKL Pomeron which manifests itself as a rapid growth of the gluon density with increasing center-of-mass energy. Although the rise of this density is indeed observed in the deep inelastic experiments at small values of Bjorken x, it is not compatible quantitatively with the prediction of the BFKL Pomeron. This lead to the intensive investigation of the possible corrections to the BFKL Pomeron such as higher order and the high density corrections. In this talk I will give an introduction to the high energy limit of QCD and discuss the idea of the parton saturation, an effect that is expected to occur when the gluon density is very high. I will describe the nonlinear evolution equation (Balitsky-Kovchegov equation) for the gluon density which takes into account high density corrections and present its solution. The concept of the saturation scale and the geometrical scaling at small Bjorken x will be also introduced as well as the interesting link between parton saturation in QCD and the statistical physics. Finally, I discuss some phenomenological signatures of parton saturation and outline recent theoretical progress in developing theory with so-called Pomeron loops, corrections which go beyond the Balitsky-Kovchegov equation.