A5047991309- 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
- Quantum, superfluid, helium dynamics
- Nuclear Physics and Applications
- Advanced NMR Techniques and Applications
- Particle Accelerators and Free-Electron Lasers
- Dark Matter and Cosmic Phenomena
- Atomic and Molecular Physics
- Superconducting Materials and Applications
- Advanced Chemical Physics Studies
- Electron and X-Ray Spectroscopy Techniques
- Particle Detector Development and Performance
- Particle accelerators and beam dynamics
- Photocathodes and Microchannel Plates
- Black Holes and Theoretical Physics
- Cold Atom Physics and Bose-Einstein Condensates
- High-pressure geophysics and materials
- X-ray Spectroscopy and Fluorescence Analysis
- Muon and positron interactions and applications
- Noncommutative and Quantum Gravity Theories
- Radiation Therapy and Dosimetry
- Radiation Detection and Scintillator Technologies
Mississippi State University
2015-2024
Duke University
2005-2021
Triangle Universities Nuclear Laboratory
2004-2021
Massachusetts Institute of Technology
2000-2019
Thomas Jefferson National Accelerator Facility
1998-2018
Université Paris-Saclay
2017
Rutgers, The State University of New Jersey
2014
Hampton University
1998-2012
University of Virginia
2012
Jackson State University
2010
We report the first measurement of parity-violating asymmetry APV in elastic scattering polarized electrons from Pb208. is sensitive to radius neutron distribution (Rn). The result APV=0.656±0.060(stat)±0.014(syst) ppm corresponds a difference between radii and proton distributions Rn−Rp=0.33−0.18+0.16 fm provides electroweak observation skin which expected heavy, neutron-rich nucleus.Received 12 January 2012DOI:https://doi.org/10.1103/PhysRevLett.108.112502© 2012 American Physical Society
We report a precision measurement of the parity-violating asymmetry $A_{PV}$ in elastic scattering longitudinally polarized electrons from $^{208}$Pb. measure $A_{PV}=550\pm 16 {\rm (stat)}\pm 8\ (syst)}$ parts per billion, leading to an extraction neutral weak form factor $F_W(Q^2 = 0.00616\ GeV}^2) 0.368 \pm 0.013$. Combined with our previous measurement, extracted neutron skin thickness is $R_n-R_p=0.283 0.071$~fm. The result also yields first significant direct interior density...
We report a precise measurement of the parity-violating (PV) asymmetry A_{PV} in elastic scattering longitudinally polarized electrons from ^{48}Ca. measure A_{PV}=2668±106(stat)±40(syst) parts per billion, leading to an extraction neutral weak form factor F_{W}(q=0.8733 fm^{-1})=0.1304±0.0052(stat)±0.0020(syst) and charge minus F_{ch}-F_{W}=0.0277±0.0055. The resulting neutron skin thickness R_{n}-R_{p}=0.121±0.026(exp)±0.024(model) fm is relatively thin yet consistent with many model...
We present measurements of the ratio proton elastic electromagnetic form factors, μpGEp/GMp. The Jefferson Lab Hall A Focal Plane Polarimeter was used to determine longitudinal and transverse components recoil polarization in ep scattering; these is proportional two factors. These data reproduce observation Jones et al. [Phys. Rev. Lett. 84, 1398 (2000)], that factor decreases significantly from unity above Q2=1GeV2.Received 29 May 2001DOI:https://doi.org/10.1103/PhysRevC.64.038202©2001...
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.
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...
We have measured the neutron spin asymmetry A(n)(1) with high precision at three kinematics in deep inelastic region x=0.33, 0.47, and 0.60, Q(2)=2.7, 3.5, 4.8 (GeV/c)(2), respectively. Our results unambiguously show, for first time, that crosses zero around x=0.47 becomes significantly positive x=0.60. Combined world proton data, polarized quark distributions were extracted. results, general, agree relativistic constituent models perturbative quantum chromodynamics (PQCD) analyses based on...
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...
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.
We report on a new measurement of the parity-violating asymmetry in quasielastic electron scattering from deuteron at backward angles Q2=0.038 (GeV/c)2. This quantity provides determination neutral weak axial vector form factor nucleon, which can potentially receive large electroweak corrections. The measured A=-3.51+/-0.57 (stat)+/-0.58 (syst) ppm is consistent with theoretical predictions. also updated results previous experiment Q2=0.091 (GeV/c)2, are
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 have measured the beam-normal single-spin asymmetry $A_n$ in elastic scattering of 1-3 GeV transversely polarized electrons from $^1$H and for first time $^4$He, $^{12}$C, $^{208}$Pb. For $^1$H, $^4$He measurements are agreement with calculations that relate to imaginary part two-photon exchange amplitude including inelastic intermediate states. Surprisingly, $^{208}$Pb result is significantly smaller than corresponding prediction using same formalism. These results suggest a systematic...
We report the first measurement of $D^{\ast -}$ meson polarization in decay $B^0 \to D^{*-} \tau^+\nu_{\tau}$ using full data sample 772$\times 10^6$ $B\bar{B}$ pairs recorded with Belle detector at KEKB electron-positron collider. Our result, $F_L^{D^\ast} = 0.60 \pm 0.08 ({\rm stat}) 0.04 sys})$, where $F_L^{D^\ast}$ denotes $D^{\ast-}$ longitudinal fraction, agrees within about $1.7$ standard deviations model prediction.
Inclusive electron scattering is measured with 4.045 GeV incident beam energy from C, Fe, and Au targets. The transfers angles correspond to a kinematic range for Bjorken $x>1$ momentum ${Q}^{2}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1--7(\mathrm{GeV}/c{)}^{2}$. When analyzed in terms of the $y$-scaling function data show first time an approach scaling values initial nucleon momenta significantly greater than nuclear matter Fermi (i.e., $>0.3\mathrm{GeV}/c$).
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 ${G}_{M}^{n}$ ${Q}^{2}=0.1$...
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...
We report the first measurement of double-spin asymmetry A{LT} for charged pion electroproduction in semi-inclusive deep-inelastic electron scattering on a transversely polarized {3}He target. The kinematics focused valence quark region, 0.16<x<0.35 with 1.4<Q{2}<2.7 GeV{2}. corresponding neutron asymmetries were extracted from measured and proton over cross section ratios using effective polarization approximation. These new data probe transverse momentum dependent parton distribution...
The physics case and an experimental overview of the MOLLER (Measurement Of a Lepton Electroweak Reaction) experiment at 12 GeV upgraded Jefferson Lab are presented. A highlight Fundamental Symmetries subfield 2007 NSAC Long Range Plan was SLAC E158 measurement parity-violating asymmetry $A_{PV}$ in polarized electron-electron (M{\o}ller) scattering. proposed will improve on this result by factor five, yielding most precise weak mixing angle low or high energy anticipated over next decade....