A5080420237- 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
- Nuclear Physics and Applications
- Quantum, superfluid, helium dynamics
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Particle Accelerators and Free-Electron Lasers
- Superconducting Materials and Applications
- Atomic and Molecular Physics
- Dark Matter and Cosmic Phenomena
- Physics of Superconductivity and Magnetism
- Electron and X-Ray Spectroscopy Techniques
- Particle Detector Development and Performance
- Neutrino Physics Research
- Advanced Chemical Physics Studies
- X-ray Spectroscopy and Fluorescence Analysis
- Particle accelerators and beam dynamics
- Radiation Detection and Scintillator Technologies
- Distributed and Parallel Computing Systems
- Nuclear reactor physics and engineering
- Superconducting and THz Device Technology
Thomas Jefferson National Accelerator Facility
2015-2024
National University of San Marcos
2006-2024
Comisión Nacional de Energía Atómica
2024
European Organization for Nuclear Research
2022
Instituto Nacional de Cancerología
2020
Williams (United States)
2002-2020
William & Mary
2002-2020
Massachusetts Institute of Technology
2001-2019
American University
1984-2018
University of Ljubljana
2018
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 electric and magnetic form factors proton, GEp/GMp, was measured at Thomas Jefferson National Accelerator Facility (JLab) using recoil polarization technique. is directly proportional to transverse longitudinal components proton in elastic $\vec ep \to e\vec p$ reaction. new data presented this article span range 3.5 < Q2 5.6 GeV2 are well described by a linear fit. Also, QF2p/F1p reaches constant value above Q2=2 GeV2.
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
The deep-inelastic electron-scattering cross sections per nucleon ${\ensuremath{\sigma}}_{A}$ for D, He, Be, C, A1, Ca, Fe, Ag, and Au were measured in the kinematic range $0.09<~x<~0.9$ $2<~{Q}^{2}<~15$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$ with use of electrons energies ranging from 8 to 24.5 GeV. ratio $\frac{{\ensuremath{\sigma}}_{A}}{{\ensuremath{\sigma}}_{\mathrm{D}}}$ is consistent unity $0.1<x<0.3$. For $0.3<x<0.8$, decreases logarithmically...
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...
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 present a search at the Jefferson Laboratory for new forces mediated by sub-GeV vector bosons with weak coupling ${\ensuremath{\alpha}}^{\ensuremath{'}}$ to electrons. Such particle ${A}^{\ensuremath{'}}$ can be produced in electron-nucleus fixed-target scattering and then decay an ${e}^{+}{e}^{\ensuremath{-}}$ pair, producing narrow resonance QED trident spectrum. Using APEX test run data, we searched mass range 175--250 MeV, found no evidence...
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...
The proton elastic form factors ${\mathit{G}}_{\mathit{E}\mathit{p}}$(${\mathit{Q}}^{2}$) and ${\mathit{G}}_{\mathit{M}\mathit{p}}$(${\mathit{Q}}^{2}$) have been extracted for ${\mathit{Q}}^{2}$=1.75 to 8.83 (GeV/c${)}^{2}$ via a Rosenbluth separation ep cross section measurements in the angular range 13\ifmmode^\circ\else\textdegree\fi{}\ensuremath{\le}\ensuremath{\theta}\ensuremath{\le}90\ifmmode^\circ\else\textdegree\fi{}. ${\mathit{Q}}^{2}$ covered more than doubles that of existing...
Cross sections for deep-inelastic electron scattering from liquid deuterium, gaseous $^{4}\mathrm{He}$, and solid Be, C, Al, Ca, Fe, Ag, Au targets were measured at the Stanford Linear Accelerator Center using electrons with energies ranging 8 to 24.5 GeV. These data cover a range in Bjorken variable $x$ 0.089 0.8, momentum transfer ${Q}^{2}$ 2 15 ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$. The ratios of cross per nucleon...
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...
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 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...
This Letter shows quantitatively that the magnitude of EMC effect measured in electron deep inelastic scattering at intermediate x(B), 0.35≤x(B)≤0.7, is linearly related to short range correlation (SRC) scale factor obtained from inclusive x(B)≥1. The observed phenomenological relationship used extract ratio deuteron free pn pair cross sections and F(2)(n)/F(2)(p), neutron proton structure functions. We speculate because both SRC are dominated by high virtuality (high momentum) nucleons nucleus.
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...
Quasielastic e-d cross sections have been measured at forward and backward angles. Rosenbluth separations were done to obtain ${\mathit{R}}_{\mathit{L}}$ ${\mathit{R}}_{\mathit{T}}$ ${\mathit{Q}}^{2}$=1.75, 2.50, 3.25, 4.00 (GeV/c${)}^{2}$. The neutron form factors ${\mathit{G}}_{\mathit{E}\mathit{n}}$ ${\mathit{G}}_{\mathit{M}\mathit{n}}$ extracted using a nonrelativistic model. sensitivity deuteron wave function, relativistic corrections, models of the inelastic background are reported....
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.
Precise measurements of the proton electromagnetic form factor ratio $R = \mu_p G_E^p/G_M^p$ using polarization transfer method at Jefferson Lab have revolutionized understanding nucleon structure by revealing strong decrease $R$ with momentum $Q^2$ for $Q^2 \gtrsim 1$ GeV$^2$, in disagreement previous extractions from cross section measurements. In particular, results exposed limits applicability one-photon-exchange approximation and highlighted role quark orbital angular structure. The...
The ratio of the nucleon F_{2} structure functions, F_{2}^{n}/F_{2}^{p}, is determined by MARATHON experiment from measurements deep inelastic scattering electrons ^{3}H and ^{3}He nuclei. was performed in Hall A Facility Jefferson Lab using two high-resolution spectrometers for electron detection, a cryogenic target system which included low-activity tritium cell. data analysis used novel technique exploiting mirror symmetry nuclei, essentially eliminates many theoretical uncertainties...
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.