F. R. Wesselmann
A5042907634- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- Nuclear physics research studies
- High-Energy Particle Collisions Research
- Atomic and Subatomic Physics Research
- Advanced NMR Techniques and Applications
- Quantum, superfluid, helium dynamics
- Particle Accelerators and Free-Electron Lasers
- Nuclear Physics and Applications
- Superconducting Materials and Applications
- Atomic and Molecular Physics
- Dark Matter and Cosmic Phenomena
- Particle accelerators and beam dynamics
- X-ray Spectroscopy and Fluorescence Analysis
- Electron and X-Ray Spectroscopy Techniques
- Crystallography and Radiation Phenomena
- Photocathodes and Microchannel Plates
- Advanced Chemical Physics Studies
- Physics of Superconductivity and Magnetism
- High-pressure geophysics and materials
- Surface and Thin Film Phenomena
- Medical Imaging Techniques and Applications
- X-ray Diffraction in Crystallography
- Scientific Research and Discoveries
- Quantum and Classical Electrodynamics
Xavier University of Louisiana
2009-2022
University of Virginia
2003-2021
Xavier University
2020
Norfolk State University
2007-2019
Old Dominion University
1997-2017
Tohoku University
2013
Massachusetts Institute of Technology
2005
Duke University
1999-2000
Williams (United States)
1999-2000
Institut National de Physique Nucléaire et de Physique des Particules
1999-2000
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...
Among the most fundamental observables of nucleon structure, electromagnetic form factors are a crucial benchmark for modern calculations describing strong interaction dynamics nucleon's quark constituents; indeed, recent proton data have attracted intense theoretical interest. In this Letter, we report new measurements factor ratio using recoil polarization method, at momentum transfers Q2=5.2, 6.7, and 8.5 GeV2. By extending range Q2 which G(E)(p) is accurately determined by more than 50%,...
We report on a precision measurement of the neutron spin structure function ${g}_{1}^{n}$ using deep inelastic scattering polarized electrons by ${}^{3}\mathrm{He}$. For kinematic range $0.014<x<0.7$ and $1<{Q}^{2}<17(\mathrm{GeV}/c{)}^{2}$, we obtain $\ensuremath{\int}{0.014}^{0.7}{g}_{1}^{n}(x)dx\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ensuremath{-}0.036\ifmmode\pm\else\textpm\fi{}0.004(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.005(\mathrm{syst})$ at an average...
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...
We present new measurements of electron scattering from high-momentum nucleons in nuclei. These data allow an improved determination the strength two-nucleon correlations for several nuclei, including light nuclei where clustering effects can, first time, be examined. The also include kinematic region three-nucleon are expected to dominate.
New measurements are reported on the deuteron spin structure function g_1^d. These results were obtained from deep inelastic scattering of 48.3 GeV electrons polarized deuterons in kinematic range 0.01 < x 0.9 and 1 Q^2 40 (GeV/c)^2. first high dose electron data using lithium deuteride (6Li2H) as target material. Extrapolations performed to obtain moments g_1^d, including Gamma_1^d, net quark polarization Delta Sigma.
We have measured the spin structure functions g2p and g2d virtual photon asymmetries A2p A2d over kinematic range 0.02⩽x⩽0.8 0.7⩽Q2⩽20GeV2 by scattering 29.1 32.3 GeV longitudinally polarized electrons from transversely NH3 6LiD targets. Our g2 approximately follows twist-2 Wandzura–Wilczek calculation. The twist-3 reduced matrix elements d2p d2n are less than two standard deviations zero. data inconsistent with Burkhardt–Cottingham sum rule if there is no pathological behavior as x→0....
We report new measurements of the ratio electric form factor to magnetic neutron, G(n)(E)/G(n)(M), obtained via recoil polarimetry from quasielastic 2H(e-->,e(')n-->)1H reaction at Q2 values 0.45, 1.13, and 1.45 (GeV/c)(2) with relative statistical uncertainties 7.6% 8.4% two higher points, which points have never been achieved in polarization measurements.
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...
Proton recoil polarization was measured in the quasielastic 4He(e,e'p)3H reaction at Q{2}=0.8 and 1.3 (GeV/c){2} with unprecedented precision. The polarization-transfer coefficients are found to differ from those of 1H(e,e'p) reaction, contradicting a relativistic distorted-wave approximation favoring either inclusion medium-modified proton form factors predicted by quark-meson coupling model or spin-dependent charge-exchange final-state interaction. For first time, ratio is studied as...
Intensive theoretical and experimental efforts over the past decade have aimed at explaining discrepancy between data for proton electric to magnetic form factor ratio, G(E)/G(M), obtained separately from cross section polarization transfer measurements. One possible explanation this difference is a two-photon-exchange contribution. In an effort search effects beyond one-photon-exchange or Born approximation, we report measurements of observables in elastic H(e[over →],e(')p[over →])...
The GEp-III and GEp-2$\gamma$ experiments were carried out in Jefferson Lab's (JLab's) Hall C from 2007-2008, to extend the knowledge of $G_E^p/G_M^p$ highest practically achievable $Q^2$ search for effects beyond Born approximation polarization transfer observables elastic $\vec{e}p$ scattering. This article reports an expanded description common experimental apparatus data analysis procedure, results a final reanalysis both experiments, including previously unpublished full-acceptance...
Spectroscopy of a $^{10}_{\Lambda}$Be hypernucleus was carried out at JLab Hall C using the $(e,e^{\prime}K^{+})$ reaction. A new magnetic spectrometer system (SPL+HES+HKS), specifically designed for high resolution hypernuclear spectroscopy, used to obtain an energy spectrum with 0.78 MeV (FWHM). The well-calibrated present experiment $p(e,e^{\prime}K^{+})\Lambda,\Sigma^{0}$ reactions allowed us determine levels, and binding ground state peak (mixture 1$^{-}$ 2$^{-}$ states) obtained be...
We report values for the neutron electric to magnetic form factor ratio, ${G}_{\mathit{En}}/{G}_{\mathit{Mn}}$, deduced from measurements of neutron's recoil polarization in quasielastic $^{2}\mathrm{H}$$(\stackrel{\ensuremath{\rightarrow}}{e},{e}^{'}\stackrel{\ensuremath{\rightarrow}}{n})$$^{1}\mathrm{H}$ reaction, at three ${Q}^{2}$ 0.45, 1.13, and 1.45 (GeV/c)${}^{2}$. The data ${Q}^{2}=1.13$ (GeV/c)${}^{2}$ are first direct experimental ${G}_{\mathit{En}}$ employing degrees freedom...
The 1H(e,e′π+)n cross section was measured for arange of four-momentum transfer up to Q2=3.91GeV2 at values the invariant mass W above resonance region. Q2 dependence longitudinal component found be consistent with Q2-scaling prediction hard exclusive processes. This suggests that QCD factorization theorem is applicable rather low Q2. transverse term falls off slower than naive Q−8 expectation and remains appreciable even Q2=3.91GeV2.Received 12 July...
We present results from a high precision experimental study of the nuclear modification longitudinal ($F_L$) to transverse ($F_1$) structure function ratio for bound nucleons in resonance region. The inclusive electron scattering cross sections were measured Jefferson Lab Experimental Hall C on carbon and deuterium nuclei large range kinematics, allowing separations functions be performed at four-momentum transfer values $0.5 \le Q^2 \le$ 3.75~GeV$^2$. In contrast significant body...
We have measured the spin structure functions g2p and g2d virtual photon asymmetries A2p A2d over kinematic range 0.02≤x≤0.8 1.0≤Q2≤30 (GeV/c)2 by scattering 38.8 GeV longitudinally polarized electrons from transversely NH3 6LiD targets. The absolute value of A2 is significantly smaller than R positivity limit range, while g2 consistent with twist-2 Wandzura-Wilczek calculation. obtain results for twist-3 reduced matrix elements d2p, d2d d2n. Burkhardt-Cottingham sum rule integral ∫g2(x)dx...
The ratio of the proton's electric to magnetic form factor, ${G}_{E}/{G}_{M}$, can be extracted in elastic electron-proton scattering by measuring cross sections, beam-target asymmetry, or recoil polarization. Separate determinations ${G}_{E}/{G}_{M}$ sections and polarization observables disagree for ${Q}^{2}>1$ (GeV/$c){}^{2}$. Measurement a third technique might uncover an unknown systematic error either previous measurements. asymmetry has been measured at ${Q}^{2}$ = 1.51...
We have measured the nuclear transparency of A(e,e′π+) process in H2, C12, Al27, Cu63, and Au197 targets. These measurements were performed at Jefferson Laboratory over a four momentum transfer squared range Q2=1.1 to 4.7 (GeV/c)2. The was extracted as super-ratio (σA/σH) from data model pion-electroproduction nuclei without π−N final-state interactions. Q2 atomic number dependence both show deviations traditional physics expectations are consistent with calculations that include quantum...
Inclusive electron-proton and electron-deuteron inelastic cross sections have been measured at Jefferson Lab (JLab) in the resonance region, large Bjorken x, up to 0.92, four-momentum transfer squared Q2 7.5 GeV2 experiment E00-116. These measurements are used extend larger x precision, quantitative, studies of phenomenon quark-hadron duality. Our analysis confirms, both globally locally, apparent violation duality previously observed a 3.5 when data compared structure function created from...
Inclusive electron scattering from nuclear targets has been measured to extract the dependence of inelastic cross section in Hall C at Thomas Jefferson National Accelerator facility. Results are presented for 2H, 3He, 4He, 9B, 12C, 63Cu and 197Au an incident beam energy 5.77 GeV a range momentum transfer Q^2 = 2 7 (GeV/c)^2. These data improve precision existing measurements EMC effect large x, allow more detailed examinations A effect.
We have measured the neutron structure function g2n and virtual photon-nucleon asymmetry A2n over kinematic range 0.014 ⩽ × 0.7 1.0 Q2 17.0 by scattering 48.3 GeV longitudinally polarized electrons from 3He. Results for are significantly smaller than √R positivity limit most of data generally consistent with twist-2 Wandzura-Wilczek prediction. Using our we obtain results twist-3 reduced matrix element d2n, integral ∫ g2n(x) dx in 1.0. Data this experiment combined existing to an average d2n dx.