A5002103856- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Nuclear physics research studies
- Atomic and Subatomic Physics Research
- Advanced NMR Techniques and Applications
- Particle Accelerators and Free-Electron Lasers
- Quantum, superfluid, helium dynamics
- Dark Matter and Cosmic Phenomena
- Nuclear Physics and Applications
- Superconducting Materials and Applications
- Crystallography and Radiation Phenomena
- Particle Detector Development and Performance
- Electron and X-Ray Spectroscopy Techniques
- Advanced Chemical Physics Studies
- Radiation Detection and Scintillator Technologies
- Atomic and Molecular Physics
- Particle accelerators and beam dynamics
- X-ray Spectroscopy and Fluorescence Analysis
- Cold Fusion and Nuclear Reactions
- High-pressure geophysics and materials
- Online and Blended Learning
- Advanced Electron Microscopy Techniques and Applications
- Quantum chaos and dynamical systems
- Methane Hydrates and Related Phenomena
Mississippi State University
2014-2023
Galway Clinic
2022
Thomas Jefferson National Accelerator Facility
2000-2017
Fermi National Accelerator Laboratory
1998-2004
American University
1993-1999
University of Pennsylvania
1997
William & Mary
1997
University of Roehampton
1997
University of Virginia
1997
Rensselaer Polytechnic Institute
1997
The spin structure function of the neutron gn1 has been determined over range 0.03<x<0.6 at an average Q2 2 (GeV/c)2 by measuring asymmetry in deep inelastic scattering polarized electrons from a 3He target energies between 19 and 26 GeV. integral is found to be F10gn1(x)dx=-0.022±0.011. Earlier reported proton results together with Bjorken sum rule predict F10gn1(x)dx=-0.059±0.019.Received 1 April 1993DOI:https://doi.org/10.1103/PhysRevLett.71.959©1993 American Physical Society
Measurements are reported of the proton and deuteron spin structure functions ${g}_{1}^{p}$ ${g}_{1}^{d}$ at beam energies 29.1, 16.2, 9.7 GeV, ${g}_{2}^{p}$ ${g}_{2}^{d}$ a energy 29.1 GeV. The integrals ${\ensuremath{\Gamma}}_{p}={\ensuremath{\int}}_{0}^{1}{g}_{1}^{p}{(x,Q}^{2})dx$ ${\ensuremath{\Gamma}}_{d}={\ensuremath{\int}}_{0}^{1}{g}_{1}^{d}{(x,Q}^{2})dx$ were evaluated fixed ${Q}^{2}=3(\mathrm{GeV}{/c)}^{2}$ using full data set to yield...
We have measured the ratio $\frac{{g}_{1}^{p}}{{F}_{1}^{p}}$ over range $0.029<x<0.8$ and $1.3<{Q}^{2}<10$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$ using deep-inelastic scattering of polarized electrons from ammonia. An evaluation integral $\ensuremath{\int}{0}^{1}{g}_{1}^{p}(x, {Q}^{2})\mathrm{dx}$ at fixed ${Q}^{2}=3$ yields 0.127\ifmmode\pm\else\textpm\fi{}0.004(stat)\ifmmode\pm\else\textpm\fi{}0.010(syst), in agreement with previous experiments, but well below Ellis-Jaffe sum...
Separated longitudinal and transverse structure functions for the reaction 1H(e,e(')pi(+))n were measured in momentum transfer region Q2 = 0.6--1.6 (GeV/c)(2) at a value of invariant mass W 1.95 GeV. New values pion charge form factor extracted from cross section by using recently developed Regge model. The results indicate that this is larger than previously assumed consistent with monopole parametrization fitted to very low elastic data.
The neutron longitudinal and transverse asymmetries A1n A2n have been extracted from deep inelastic scattering of polarized electrons by a He3 target at incident energies 19.42, 22.66, 25.51 GeV. measurement allows for the determination spin structure functions g1n(x, Q2) g2n(x, over range 0.03<x<0.6 an average Q2 2 (GeV/c)2. data are used evaluation Ellis-Jaffe Bjorken sum rules. function is small negative within our measurement, yielding integral ∫0.030.6g1n(x)dx=−0.028±0.006 (stat)±0.006...
The charged pion form factor, ${F}_{\ensuremath{\pi}}({Q}^{2})$, is an important quantity that can be used to advance our knowledge of hadronic structure. However, the extraction ${F}_{\ensuremath{\pi}}$ from data requires a model ${}^{1}\mathrm{H}(e,{e}^{'}{\ensuremath{\pi}}^{+})n$ reaction and thus inherently dependent. Therefore, detailed description factor electroproduction obtained recently at Jefferson Lab presented, with particular focus given dominant uncertainties in this procedure....
We report on a high-statistics measurement of the deuteron spin structure function ${g}_{1}^{d}$ at beam energy 29 GeV in kinematic range $0.029<x<0.8$ and $1<{Q}^{2}<10$ (GeV $/c$${)}^{2}$. The integral ${\ensuremath{\gamma}}_{1}^{d}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ensuremath{\int}{1}^{}{g}_{1}^{d}\mathrm{dx}$ evaluated fixed ${Q}^{2}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}3$ $/c$${)}^{2}$ gives...
We report on precision measurements of the elastic cross section for electron-proton scattering performed in Hall C at Jefferson Lab. The were made 28 distinct kinematic settings covering a range momentum transfer $0.4<{Q}^{2}<5.5\phantom{\rule{0.3em}{0ex}}{(\mathrm{GeV}∕c)}^{2}$. These represent significant contribution to world's data set ${Q}^{2}$ range, where large discrepancy currently exists between ratio electric magnetic proton form factors extracted from previous and that recently...
The data analysis for the reaction H(e,e' pi^+)n, which was used to determine values charged pion form factor Fpi of Q^2=0.6-1.6 GeV^2, has been repeated with careful inspection all steps and special attention systematic uncertainties. Also method extract from measured longitudinal cross section critically reconsidered. Final separated transverse sections extracted are presented.
New Jefferson Lab data are presented on the nuclear dependence of inclusive cross section from $^{2}\mathrm{H}$, $^{3}\mathrm{He}$, $^{4}\mathrm{He}$, $^{9}\mathrm{Be}$ and $^{12}\mathrm{C}$ for $0.3<x<0.9$, ${Q}^{2}\ensuremath{\approx}3--6\text{ }\text{ }{\mathrm{GeV}}^{2}$. These represent first measurement EMC effect $^{3}\mathrm{He}$ at large $x$ a significant improvement $^{4}\mathrm{He}$. The do not support previous $A$-dependent or density-dependent fits to suggest that quark...
The Q(weak) experiment has measured the parity-violating asymmetry in ep elastic scattering at Q(2)=0.025(GeV/c)(2), employing 145 μA of 89% longitudinally polarized electrons on a 34.4 cm long liquid hydrogen target Jefferson Lab. results experiment's commissioning run, constituting approximately 4% data collected experiment, are reported here. From these initial results, is A(ep)=-279±35 (stat) ± 31 (syst) ppb, which smallest and most precise ever scattering. small Q(2) this made possible...
We studied the electroproduction of $\ensuremath{\Delta}(1232)$ resonance via reaction $p({e,e}^{\ensuremath{'}}p){\ensuremath{\pi}}^{0}$ at four-momentum transfers ${Q}^{2}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}2.8\mathrm{and}4.0{\mathrm{GeV}}^{2}$. This is highest ${Q}^{2}$ for which exclusive has ever been observed. Decay angular distributions $\ensuremath{\Delta}\ensuremath{\rightarrow}p{\ensuremath{\pi}}^{0}$ were measured over a wide range barycentric energies covering...
The electric form factor of the neutron was determined from measurements $\stackrel{\ensuremath{\rightarrow}}{d}(\stackrel{\ensuremath{\rightarrow}}{e},{e}^{\ensuremath{'}}n)p$ reaction for quasielastic kinematics. Polarized electrons were scattered off a polarized deuterated ammonia ($^{15}\mathrm{N}\mathrm{D}_{3}$) target in which deuteron polarization perpendicular to momentum transfer. detected magnetic spectrometer coincidence with neutrons large solid angle detector. We find...
We have measured proton and deuteron virtual photon-nucleon asymmetries ${A}_{2}^{p}$ ${A}_{2}^{d}$ structure functions ${g}_{2}^{p}$ ${g}_{2}^{d}$ over the range $0.03<x<0.8$ $1.3<{Q}^{2}<10(\mathrm{GeV}/c{)}^{2}$ by inelastically scattering polarized electrons off ammonia targets. Results for ${A}_{2}$ are significantly smaller than positivity limit $\sqrt{R}$ both Within experimental precision ${g}_{2}$ data well described twist-2 contribution, ${g}_{2}^{\mathrm{WW}}$. Twist-3 matrix...
Cross sections for the reaction ${}^{1}\mathrm{H}(e,{e}^{'}{\ensuremath{\pi}}^{+})n$ were measured in Hall C at Thomas Jefferson National Accelerator Facility (JLab) using high-intensity Continuous Electron Beam (CEBAF) to determine charged pion form factor. Data taken central four-momentum transfers ranging from ${Q}^{2}=0.60$ 2.45 ${\mathrm{GeV}}^{2}$ an invariant mass of virtual photon-nucleon system $W=1.95$ and 2.22 GeV. The cross separated into four structure functions...
A newly obtained sample of inclusive electron-nucleon scattering data has been analyzed for precision tests quark-hadron duality. The are in the nucleon resonance region, and span range 0. 3<Q2<5.0 (GeV/c)(2). Duality is observed both limited extended regions around prominent enhancements. Higher twist contributions to F2 structure function found be small on average, even low Q2 regime approximately 0.5 Using duality, an average scaling curve obtained. In all cases, duality appears a...
Tensor polarization observables ( t20, t21, and t22) have been measured in elastic electron-deuteron scattering for six values of momentum transfer between 0.66 1.7(GeV/c)2. The experiment was performed at the Jefferson Laboratory Hall C using electron High Momentum Spectrometer, a specially designed deuteron magnetic channel recoil polarimeter POLDER. new data determine to much larger Q2 charge form factors GC GQ. They are good agreement with relativistic calculations disagree perturbative...
A newly obtained data sample of inclusive electron-nucleon scattering from both hydrogen and deuterium targets is analyzed. These JLab span the nucleon resonance region up to four-momentum transfers 5 (GeV/c)(2). The are found follow an average scaling curve. inclusion low-momentum transfer yields a curve resembling deep inelastic neutrino-nucleus data, suggesting sensitivity valencelike structure only.