A5002997734- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- Nuclear physics research studies
- High-Energy Particle Collisions Research
- Nuclear Physics and Applications
- Advanced NMR Techniques and Applications
- Atomic and Subatomic Physics Research
- Quantum, superfluid, helium dynamics
- Radiation Detection and Scintillator Technologies
- Particle Accelerators and Free-Electron Lasers
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- Particle Detector Development and Performance
- Atomic and Molecular Physics
- Neutrino Physics Research
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced Chemical Physics Studies
- Medical Imaging Techniques and Applications
- Dark Matter and Cosmic Phenomena
- Nuclear reactor physics and engineering
- Cold Atom Physics and Bose-Einstein Condensates
- Rare-earth and actinide compounds
- Magnetic confinement fusion research
- Electron and X-Ray Spectroscopy Techniques
- Photocathodes and Microchannel Plates
Idaho State University
2008-2020
University of Kentucky
2003-2013
Pacific Northwest National Laboratory
2012
National Technical Information Service
2012
Office of Scientific and Technical Information
2012
United States Department of Commerce
2012
Idaho National Laboratory
2012
Universidade de São Paulo
2010
Brigham Young University - Idaho
2010
Campbell Collaboration
2008
The ratio of the proton's elastic electromagnetic form factors, G(E(p))/G(M(p)), was obtained by measuring P(t) and P(l), transverse longitudinal recoil proton polarization, respectively. For e-->p-->ep-->, G(E(p))/G(M(p)) is proportional to P(t)/P(l). Simultaneous measurement P(l) in a polarimeter provides good control systematic uncertainty. results for show decrease as Q2 increases from 0.5 3.5 GeV2, indicating first time definite difference spatial distribution charge magnetization...
The ratio of the proton elastic electromagnetic form factors, ${G}_{\mathit{Ep}}/{G}_{\mathit{Mp}}$, was obtained by measuring ${P}_{t}$ and ${P}_{\ensuremath{\ell}}$, transverse longitudinal recoil polarization components, respectively, for $\stackrel{\ensuremath{\rightarrow}}{e}p\ensuremath{\rightarrow}e\stackrel{\ensuremath{\rightarrow}}{p}$reaction in four-momentum transfer squared range 0.5 to $3.5\phantom{\rule{0.3em}{0ex}}\text{GeV}{}^{2}$. In single-photon exchange approximation,...
We have measured parity-violating asymmetries in elastic electron-proton scattering over the range of momentum transfers 0.12 < or =Q2 =1.0 GeV2. These asymmetries, arising from interference electromagnetic and neutral weak interactions, are sensitive to strange-quark contributions currents proton. The measurements were made at Jefferson Laboratory using a toroidal spectrometer detect recoiling protons liquid hydrogen target. results indicate nonzero, Q2 dependent, provide new information...
We have measured the parity-violating electroweak asymmetry in elastic scattering of polarized electrons from protons. Significant contributions to this could arise strange form factors nucleon. The is $A=\ensuremath{-}15.05\ifmmode\pm\else\textpm\fi{}0.98(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.56(\mathrm{syst})\phantom{\rule{0.3em}{0ex}}\mathrm{ppm}$ at kinematic point $⟨{\ensuremath{\theta}}_{\mathrm{lab}}⟩=12.3\ifmmode^\circ\else\textdegree\fi{}$ and...
The Polarized Electrons for Positrons experiment at the injector of Continuous Electron Beam Accelerator Facility has demonstrated first time efficient transfer polarization from electrons to positrons produced by polarized bremsstrahlung radiation induced a electron beam in high-Z target. Positron up 82% have been measured an initial momentum 8.19 MeV/c, limited only polarization. This technique extends positron capabilities GeV MeV beams, and opens access physics wide community.
We have measured the transverse asymmetry ${A}_{{T}^{\ensuremath{'}}}$ in ${}^{3}\stackrel{\ensuremath{\rightarrow}}{\mathrm{He}}(\stackrel{\ensuremath{\rightarrow}}{e}{,e}^{\ensuremath{'}})$ quasielastic scattering Hall A at Jefferson Laboratory with high precision for ${Q}^{2}$ values from 0.1 to $0.6(\mathrm{GeV}/c{)}^{2}$. The neutron magnetic form factor ${G}_{M}^{n}$ was extracted based on Faddeev calculations ${Q}^{2}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.1$ and...
Recoil proton polarization observables were measured for both the p(e→,e′p→) and d(e→,e′p→)n reactions at two values of Q2 using a newly commissioned focal plane polarimeter MIT-Bates Linear Accelerator Center. The hydrogen deuterium spin-dependent Dℓℓ Dℓt, induced Pn, form factor ratio GEp/GMp under identical kinematics. results are in good agreement with each other plane-wave impulse approximation (PWIA).Received 8 August 1997DOI:https://doi.org/10.1103/PhysRevLett.80.452©1998 American...
We have measured the parity-violating electroweak asymmetry in elastic scattering of polarized electrons from proton. The kinematic point [ $〈{\ensuremath{\theta}}_{\mathrm{lab}}〉\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}12.3\ifmmode^\circ\else\textdegree\fi{}$ and $〈{Q}^{2}〉\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.48(\mathrm{GeV}/c{)}^{2}$] is chosen to provide sensitivity, at a level that theoretical interest, strange electric form factor ${G}_{E}^{s}$. result,...
This paper was published online on 20 May 2005 without several of the authors’ corrections incorporated. Equation (13) has been replaced. The captions Figs. 16–18 have also Typographical errors pages 4, 6, 14, 15, 18, 19, 22, and 24 all corrected. corrected as 8 June 2005. text is correct in printed version journal.Received 6 2005DOI:https://doi.org/10.1103/PhysRevC.71.069902©2005 American Physical Society
High precision measurements of the differential cross sections for π0 photoproduction at forward angles two nuclei, 12C and 208Pb, have been performed incident photon energies 4.9-5.5 GeV to extract π0→γγ decay width. The experiment was done Jefferson Lab using Hall B tagger a high-resolution multichannel calorimeter. width extracted by fitting measured recently updated theoretical models process. resulting value is Γ(π0→γγ)=7.82±0.14(stat)±0.17(syst) eV. With 2.8% total uncertainty, this...
The neutron elastic magnetic form factor GMn has been extracted from quasielastic electron scattering data on deuterium with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. kinematic coverage of measurement is continuous Q2=1 GeV2 to 4.8 GeV2. High precision was achieved by employing a ratio technique in which many uncertainties cancel, and simultaneous in-situ calibration detection efficiency, largest correction data. Neutrons were detected using CLAS electromagnetic...
A search for the Θ+ in reaction γd→pK−K+n was completed using CLAS detector at Jefferson Lab. study of same reaction, published earlier, reported observation a narrow resonance. The present experiment, with more than 30 times integrated luminosity our earlier measurement, does not show any evidence pentaquark angle-integrated upper limit on production mass range 1.52–1.56 GeV/c2 γd→pK−Θ+ is 0.3 nb (95% C.L.). This depends assumptions made and angular distribution production. Using Λ(1520) as...
The deuteron elastic structure function $A({Q}^{2})$ has been extracted in the range $0.7\ensuremath{\le}{Q}^{2}\ensuremath{\le}6.0(\mathrm{GeV}/c{)}^{2}$ from cross section measurements of electron-deuteron scattering coincidence using Hall A Facility Jefferson Laboratory. data are compared to theoretical models, based on impulse approximation with inclusion meson-exchange currents, and predictions quark dimensional scaling perturbative quantum chromodynamics.
A high precision measurement of the transverse spin-dependent asymmetry ${A}_{{T}^{\ensuremath{'}}}$ in ${}^{3}\mathrm{He}\ensuremath{\rightarrow}(\stackrel{\ensuremath{\rightarrow}}{e}{,e}^{\ensuremath{'}})$ quasielastic scattering was performed Hall at Jefferson Lab values squared four-momentum transfer, ${Q}^{2},$ between 0.1 and 0.6 $(\mathrm{G}\mathrm{e}\mathrm{V}/{c)}^{2}.$ is sensitive to neutron magnetic form factor, ${G}_{M}^{n}.$ Values ${G}_{M}^{n}$ ${Q}^{2}=0.1$...
The distribution of $M1$ strength in $^{208}\mathrm{Pb}$ has been measured between 5.8 and 7.4 MeV with highly polarized tagged photons. $\ensuremath{\Sigma}\frac{{\ensuremath{\Gamma}}_{0}^{2}(M1)}{\ensuremath{\Gamma}}={14.6}_{\ensuremath{-}1.3}^{+1.5}$ eV corresponding to $\ensuremath{\Sigma}B(M1\ensuremath{\uparrow})=({10.7}_{\ensuremath{-}0.9}^{+1.1}){\ensuremath{\mu}}_{N}^{2}$ was found, can fully account for the much discussed "missing" $^{208}\mathrm{Pb}$. When present result is...
The exclusive reaction gammap-->K0K+n was studied in the photon energy range between 1.6 and 3.8 GeV searching for evidence of exotic baryon Theta+ (1540)-->nK+. decay to nK+requires assignment strangeness S=+1 any observed resonance. Data were collected with CLAS detector at Thomas Jefferson National Accelerator Facility corresponding an integrated luminosity 70 pb-1. No pentaquark found. Upper limits set on production cross section as function center-of-mass angle nK+ mass. 95% C.L. upper...
The helicity amplitudes of the electroexcitation Roper resonance are extracted for 1.7 < Q2 4.5 GeV2 from recent high precision JLab-CLAS cross section and longitudinally polarized beam asymmetry data pi+ electroproduction on protons at W=1.15-1.69 GeV. analysis is made using two approaches, dispersion relations a unitary isobar model, which give consistent results. It found that transverse amplitude A_{1/2} gamma* p -> N(1440)P11 transition, large negative Q2=0, becomes positive ~ 2 GeV2,...
The exclusive electroproduction process $\vec{e}p \to e^\prime n \pi^+$ was measured in the range of photon virtuality $Q^2 = 1.7 - 4.5 \rm{GeV^2}$, and invariant mass for $n\pi^+$ system $W 1.15 \rm{GeV}$ using CEBAF Large Acceptance Spectrometer. For first time, these kinematics are probed $\pi^+$ production from protons with nearly full coverage azimuthal polar angles center-of-mass system. channel has particular sensitivity to isospin 1/2 excited nucleon states, together $p\pi^0$ final...
The explicit breaking of the axial symmetry by quantum fluctuations gives rise to so-called anomaly. This phenomenon is solely responsible for decay neutral pion π0 into two photons (γγ), leading its unusually short lifetime. We precisely measured width Γ [Formula: see text] process. differential cross sections photoproduction at forward angles were on targets, carbon-12 and silicon-28, yielding text], where stat. denotes statistical uncertainty syst. systematic uncertainty. combined results...
We have measured the transverse asymmetry AT' in quasielastic 3He→(e→,e') process with high precision at Q2 values from 0.1 to 0.6(GeV/c)2. The neutron magnetic form factor GMn was extracted of and 0.2(GeV/c)2 using a nonrelativistic Faddeev calculation which includes both final-state interactions (FSI) meson-exchange currents (MEC). Theoretical uncertainties due FSI MEC effects were constrained measurement spin-dependent threshold region 3He→(e→,e'). also 0.3 0.6(GeV/c)2 based on plane wave...
The spin structure functions g_1 for the proton and deuteron have been measured over a wide kinematic range in x Q2 using 1.6 5.7 GeV longitudinally polarized electrons incident upon NH_3 ND_3 targets at Jefferson Lab. Scattered were detected CEBAF Large Acceptance Spectrometer, 0.05 < Q^2 5 GeV^2 W 3 GeV. first moments of are presented -- both negative slope low Q^2, as predicted by extended Gerasimov-Drell-Hearn sum rule. result generalized forward polarizability gamma_0^p is also...