A5046119137- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- Atomic and Subatomic Physics Research
- High-Energy Particle Collisions Research
- Nuclear physics research studies
- Advanced NMR Techniques and Applications
- Quantum, superfluid, helium dynamics
- Nuclear Physics and Applications
- Superconducting Materials and Applications
- Particle Accelerators and Free-Electron Lasers
- Atomic and Molecular Physics
- Physics of Superconductivity and Magnetism
- Dark Matter and Cosmic Phenomena
- Particle Detector Development and Performance
- Advanced Chemical Physics Studies
- Electron and X-Ray Spectroscopy Techniques
- Methane Hydrates and Related Phenomena
- Neutrino Physics Research
- Inorganic Fluorides and Related Compounds
- Crystallography and Radiation Phenomena
- Radiation Detection and Scintillator Technologies
- Black Holes and Theoretical Physics
- Astronomical and nuclear sciences
- Scientific Research and Discoveries
- Computational Physics and Python Applications
Thomas Jefferson National Accelerator Facility
2017-2024
University of New Hampshire
2014-2024
University of New Hampshire at Manchester
2009-2024
Temple University
1995-2022
University of Virginia
2008-2022
Oak Ridge National Laboratory
2022
William & Mary
2020
Williams (United States)
2020
Tel Aviv University
2008
Massachusetts Institute of Technology
2001-2008
The protons and neutrons in a nucleus can form strongly correlated nucleon pairs. Scattering experiments, where proton is knocked-out of the with high momentum transfer missing momentum, show that 12C neutron-proton pairs are nearly twenty times as prevalent proton-proton and, by inference, neutron-neutron This difference between types due to nature strong force has implications for understanding cold dense nuclear systems such neutron stars.
We report the results of a new Rosenbluth measurement proton electromagnetic form factors at Q2 values 2.64, 3.20, and 4.10 GeV2. Cross sections were determined by detecting recoiling proton, in contrast to previous measurements which detected scattered electron. 3%, with relative uncertainties below 1%. The ratio mu(p)G(E)/G(M) was 4%-8% showed approximately 1. These are consistent with, much more precise than, extractions. They inconsistent recent polarization transfer similar precision,...
We report new measurements of the parity-violating asymmetry ${A}_{\mathrm{PV}}$ in elastic scattering 3 GeV electrons off hydrogen and $^{4}\mathrm{He}$ targets with $⟨{\ensuremath{\theta}}_{\mathrm{lab}}⟩\ensuremath{\approx}6.0\ifmmode^\circ\else\textdegree\fi{}$. The result is ${A}_{\mathrm{PV}}=\mathbf{(}+6.40\ifmmode\pm\else\textpm\fi{}0.23(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.12(\mathrm{syst})\mathbf{)}\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$....
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 report on measurements of the neutron spin asymmetries An1,2 and polarized structure functions gn1,2 at three kinematics in deep inelastic region, with x=0.33, 0.47, 0.60 Q2=2.7, 3.5, 4.8(GeV∕c)2, respectively. These were performed using a 5.7GeV longitudinally electron beam 3He target. The results for An1 gn1 x=0.33 are consistent previous world data and, two higher-x points, have improved precision by about an order magnitude. new show zero crossing around x=0.47 value x=0.60 is...
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 present the first measurements of $\stackrel{\ensuremath{\rightarrow}}{e}p\ensuremath{\rightarrow}ep\ensuremath{\gamma}$ cross section in deeply virtual Compton scattering (DVCS) regime and valence quark region. The ${Q}^{2}$ dependence (from 1.5 to $2.3\text{ }\text{ }{\mathrm{GeV}}^{2}$) helicity-dependent indicates twist-2 dominance DVCS, proving that generalized parton distributions (GPDs) are accessible experiment at moderate ${Q}^{2}$. helicity-independent is also measured...
We investigated simultaneously the 12C(e,e'p) and 12C(e,e'pp) reactions at Q2=2 (GeV/c)2, xB=1.2, in an (e, e'p) missing-momentum range from 300 to 600 MeV/c. At these kinematics, with a missing momentum greater than Fermi of nucleons nucleus far delta excitation, short-range nucleon-nucleon correlations are predicted dominate reaction. For (9.5+/-2)% events, recoiling partner proton was observed back-to-back vector, experimental signature correlations.
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...
The present experiment exploits the interference between Deeply Virtual Compton Scattering (DVCS) and Bethe-Heitler processes to extract imaginary part of DVCS amplitudes on neutron deuteron from helicity-dependent D$({\vec e},e'\gamma)X$ cross section measured at $Q^2$=1.9 GeV$^2$ $x_B$=0.36. We a linear combination generalized parton distributions (GPDs) particularly sensitive $E_q$, least constrained GPD. A model dependent constraint contribution up down quarks nucleon spin is deduced.
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...
We present an updated extraction of the proton electromagnetic form factor ratio, ${\ensuremath{\mu}}_{p}{G}_{E}/{G}_{M}$, at low ${Q}^{2}$. The factors are sensitive to spatial distribution proton, and precise measurements can be used constrain models proton. An improved selection elastic events reduced background contributions yielded a small systematic reduction in ratio ${\ensuremath{\mu}}_{p}{G}_{E}/{G}_{M}$ compared original analysis.
We present final results on the photon electroproduction ($\vec{e}p\rightarrow ep\gamma$) cross section in deeply virtual Compton scattering (DVCS) regime and valence quark region from Jefferson Lab experiment E00-110. Results an analysis of a subset these data were published before, but has been improved which is described here at length, together with details experimental setup. Furthermore, additional have analyzed resulting sections new kinematic settings, for total 588 bins. $Q^2$-...
We present new data on the Bjorken sum $\overline \Gamma_1^{p-n}(Q^2)$ at 4-momentum transfer $ 0.021 \leq Q^2 0.496$ GeV$^2$. The were obtained in two experiments performed Jefferson Lab: EG4 polarized protons and deuterons, E97110 $^3$He from which neutron extracted. cover domain where chiral effective field theory ($\chi$EFT), leading of Strong Force large distances, is expected to be applicable. find that our predictions $\chi$EFT are only marginal agreement. This somewhat surprising as...
We extract the Bjorken integral ${\ensuremath{\Gamma}}_{1}^{p\mathrm{\text{\ensuremath{-}}}n}$ in range $0.17<{Q}^{2}<1.10\text{ }\text{ }{\mathrm{G}\mathrm{e}\mathrm{V}}^{2}$ from inclusive scattering of polarized electrons by protons, deuterons, and $^{3}\mathrm{H}\mathrm{e}$, for region which is dominated nucleon resonances. These data bridge domains hadronic partonic descriptions nucleon. In combination with earlier measurements at higher ${Q}^{2}$, we nonsinglet twist-4 matrix element ${f}_{2}$.
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 present data on the inclusive scattering of polarized electrons from a 3He target at energies 0.862 to 5.06 GeV, obtained angle 15.5°. Our include measurements quasielastic peak, through nucleon resonance region, and beyond, were used determine virtual photon cross-section difference σ1/2−σ3/2. extract extended Gerasimov-Drell-Hearn integral for neutron in range four-momentum transfer squared Q2 0.1–0.9 GeV2.Received 15 May 2002DOI:https://doi.org/10.1103/PhysRevLett.89.242301©2002...
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 spin structure functions $g_1$ and $g_2$ of $^3$He in a double-spin experiment by inclusively scattering polarized electrons at energies ranging from 0.862 to 5.07 GeV off target 15.5$^{\circ}$ angle. Excitation covered resonance onset deep inelastic regions. determined for first time $Q^2$ evolution $\Gamma_1(Q^2)=\int_0^{1} g_1(x,Q^2) dx$, $\Gamma_2(Q^2)=\int_0^1 g_2(x,Q^2) dx$ $d_2 (Q^2) = \int_0^1 x^2[ 2g_1(x,Q^2) + 3g_2(x,Q^2)] neutron range 0.1 GeV$^2$ $\leq Q^2...
Inclusive electron scattering from nuclear targets has been measured to extract the dependence of inelastic cross section in Hall C at Thomas Jefferson National Accelerator facility. Results are presented for 2H, 3He, 4He, 9B, 12C, 63Cu and 197Au an incident beam energy 5.77 GeV a range momentum transfer Q^2 = 2 7 (GeV/c)^2. These data improve precision existing measurements EMC effect large x, allow more detailed examinations A effect.
We present results from a high precision experimental study of the nuclear modification longitudinal ($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 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 $^{2}\mathrm{H}(e,{e}^{\ensuremath{'}}p)n$ cross section at a momentum transfer of $3.5\text{ }\text{ }(\mathrm{GeV}/c{)}^{2}$ was measured over kinematical range that made it possible to study this reaction for set fixed missing momenta as function the neutron recoil angle ${\ensuremath{\theta}}_{\mathrm{nq}}$ and extract distributions values up $0.55\text{ }\mathrm{GeV}/c$. In region...
High-precision measurements of the proton elastic form-factor ratio, ${\ensuremath{\mu}}_{p}{G}_{E}^{p}/{G}_{M}^{p}$, have been made at four-momentum transfer, ${Q}^{2}$, values between 0.2 and $0.5\text{ }\text{ }{\mathrm{GeV}}^{2}$. The new data, while consistent with previous results, clearly show a ratio less than unity significant differences from central several recent phenomenological fits. By combining data an existing cross-section measurement, one finds that in this ${Q}^{2}$ range...