A5003921836- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Nuclear physics research studies
- Particle Accelerators and Free-Electron Lasers
- Particle Detector Development and Performance
- Advanced NMR Techniques and Applications
- Atomic and Subatomic Physics Research
- High-pressure geophysics and materials
- Quantum, superfluid, helium dynamics
- Advanced Chemical Physics Studies
- Nuclear Physics and Applications
- Molecular Spectroscopy and Structure
- Topological Materials and Phenomena
- Nuclear reactor physics and engineering
- Particle accelerators and beam dynamics
- Magnetic confinement fusion research
- Advanced X-ray Imaging Techniques
- Radiopharmaceutical Chemistry and Applications
- Seismic Imaging and Inversion Techniques
- Ammonia Synthesis and Nitrogen Reduction
- Dark Matter and Cosmic Phenomena
- Superconducting Materials and Applications
- Advanced Memory and Neural Computing
- Physics of Superconductivity and Magnetism
Center for High Pressure Science and Technology Advanced Research
2024
Center for High Pressure Science & Technology Advanced Research
2024
Hampton University
2003-2022
American University
2003-2022
Ohio University
2006-2018
Ohio University Lancaster
2007-2012
Old Dominion University
2001
American University in Cairo
2001
University of Massachusetts Amherst
2001
We report on precision measurements of the elastic cross section for electron-proton scattering performed in Hall C at Jefferson Lab. The were made 28 distinct kinematic settings covering a range momentum transfer $0.4<{Q}^{2}<5.5\phantom{\rule{0.3em}{0ex}}{(\mathrm{GeV}∕c)}^{2}$. These represent significant contribution to world's data set ${Q}^{2}$ range, where large discrepancy currently exists between ratio electric magnetic proton form factors extracted from previous and that recently...
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....
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...
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...
The spin alignment of $J/\psi$ with respect to event plane in relativistic heavy ion collisions exhibits a significant signal. We propose possible mechanism for through dependent dissociation quarkonia vortical quark-gluon plasma. is realized inelastic scattering between constituents quarkonium and those plasma polarized by the vorticity. rate found depend on directions vorticity, quantization axis, quark momentum. implement our results dominated evolution model Bjorken flow, finding $0$...
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...
High-energy, cw electron beams at new accelerator facilities allow electromagnetic production and precision study of hypernuclear structure, we report here on the first experiment demonstrating potential $(e,{e}^{\ensuremath{'}}{K}^{+})$ reaction for spectroscopy. This is also to take advantage enhanced virtual photon flux available when electrons are scattered approximately zero degrees. The observed energy resolution was found be $\ensuremath{\approx}900\text{ }\text{...
The effects of two-photon exchange corrections, suggested to explain the difference between measurements proton elastic electromagnetic form factors using polarization transfer and Rosenbluth techniques, have been studied in inelastic scattering data. Such corrections could introduce epsilon-dependent non-linearities separations, where epsilon is virtual photon parameter. It concluded that such non-linear are consistent with zero for elastic, resonance, deep-inelastic all Q^2 W^2 values measured.
Cross sections for semi-inclusive electroproduction of charged pions (π±) from both proton and deuteron targets were measured 0.2<x<0.5, 2<Q2<4 GeV2, 0.3<z<1, Pt2<0.2 GeV2. For Pt<0.1 GeV, we find the azimuthal dependence to be small, as expected theoretically. π+ π−, Pt is found slightly weaker than proton. In context a simple model, this implies that initial transverse momenta width d quarks larger u and, contrary expectations, momentum favored fragmentation function unfavored one.
We have examined the spin structure of proton in region nucleon resonances (1.085 GeV<W<1.910 GeV) at an average four momentum transfer Q2=1.3 GeV2. Using Jefferson Lab polarized electron beam, a spectrometer, and solid target, we measured asymmetries A∥ A⊥ to high precision, extracted A1 A2, functions g1 g2. found notably nonzero A⊥, significant contributions from higher-twist effects, only weak support for quark-hadron duality.Received 1 August...
The differential cross section for the process $p(e,{e}^{'}p)\ensuremath{\eta}$ has been measured at ${Q}^{2}~5.7$ and $7.0(\mathrm{GeV}/c){}^{2}$ center-of-mass energies from threshold to 1.8 GeV, encompassing ${S}_{11}(1535)$ resonance, which dominates channel. This is highest momentum-transfer measurement of this exclusive date. helicity-conserving transition amplitude ${A}_{1/2}$, production extracted data. Within limited ${Q}^{2}$ now measured, quantity appears begin scaling as...
The first measurements of the d(gamma,p)n differential cross section at forward angles and photon energies above 4 GeV were performed Thomas Jefferson National Accelerator Facility (JLab). results indicate evidence an angular dependent scaling threshold. Results straight theta(cm) = 37 degrees are consistent with constituent counting rules for E(gamma) greater, similar GeV, while those 70 1.5 GeV.
A pioneering experiment in \ensuremath{\Lambda} hypernuclear spectroscopy, undertaken at the Thomas Jefferson National Accelerator Facility (JLab), was recently reported. The used high precision, continuous electron beam JLab, and a special arrangement of spectrometer magnets to measure spectrum from C $^{7}\mathrm{Li}$ targets using $(e,e'{K}^{+})$ reaction. ${}_{\ensuremath{\Lambda}}^{12}$B found this investigation previously published, but is reported here more detail, with improved...
A large set of cross sections for semi-inclusive electroproduction charged pions ($\pi^\pm$) from both proton and deuteron targets was measured. The data are in the deep-inelastic scattering region with invariant mass squared $W^2$ > 4 GeV$^2$ range four-momentum transfer $2 < Q^2 4$ (GeV/c)$^2$, cover a Bjorken scaling variable 0.2 x 0.6. fractional energy spans 0.3 z 1, small transverse momenta respect to virtual-photon direction, $P_t^2 0.2$ (GeV/c)$^2$. that goes undetected, $M_x$ or W',...
Structure functions, as measured in lepton-nucleon scattering, have proven to be very useful studying the quark dynamics within nucleon. However, it is experimentally difficult separately determine longitudinal and transverse structure consequently there are substantially less data available for function particular. Here we present separated functions hydrogen deuterium at low four--momentum transfer squared, Q^2< 1 GeV^2, compare these with parton distribution parameterizations a k_T...
Topological electrides have attracted extensive attention, not only serving as good platforms for studying Dirac fermion, Weyl and diverse quasiparticles beyond the fermions, but also hosting rich physical chemical properties such low work function, high conductivity, electron mobility. Motivated by synthesized YCl <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:msub><a:mi...
We have extracted QCD matrix elements from our data on doubly polarized inelastic scattering of electrons nuclei.We find the higher twist element d2, which arises strictly quarkgluon interactions, to be unambiguously non zero.The also reveal an isospin dependence effects if we assume that Burkhardt-Cottingham Sum rule is valid.The fundamental Bjorken sum obtained a0 satisfied at low momentum transfer.
Cross sections for the $^{1}\mathrm{H}$($e,{e}^{\ensuremath{'}}{\ensuremath{\pi}}^{+})n$ process on $^{1}\mathrm{H}$, $^{2}\mathrm{H}$, $^{12}\mathrm{C}$, $^{27}\mathrm{Al}$, $^{63}\mathrm{Cu}$, and $^{197}\mathrm{Au}$ targets were measured at Thomas Jefferson National Accelerator Facility (Jefferson Lab) to extract nuclear transparencies. Data taken from ${Q}^{2}=1.1$--4.7 GeV${}^{2}$ a fixed center-of-mass energy of $W=2.14$ GeV. The ratio ${\ensuremath{\sigma}}_{L}$...
We report on a study of the longitudinal to transverse cross section ratio, R=σL/σT, at low values x and Q2, as determined from inclusive inelastic electron-hydrogen electron-deuterium scattering data Jefferson Laboratory Hall C spanning four-momentum transfer range 0.06<Q2<2.8 GeV2. Even lowest R remains nearly constant does not disappear with decreasing might be expected. find identical behavior for hydrogen deuterium.Received 10 November...
We report on a detailed study of longitudinal strength in the nucleon resonance region, presenting new results from inclusive electron-proton cross sections measured at Jefferson Lab Hall C four-momentum transfer range $0.2<{Q}^{2}<5.5\phantom{\rule{4pt}{0ex}}{\mathrm{GeV}}^{2}$. The data have been used to accurately perform 167 Rosenbluth-type longitudinal/transverse separations. precision $R={\ensuremath{\sigma}}_{L}/{\ensuremath{\sigma}}_{T}$ are presented here, along with first separate...
The (3,4)(Lambda)H and (4)(Lambda)H hypernuclear bound states have been observed for the first time in kaon electroproduction on (3,4)He targets. production cross sections determined at Q(2)=0.35 GeV2 W=1.91 GeV. For either hypernucleus nuclear form factor is by comparing angular distribution of (3,4)He(e,e(')K+)(3,4)(Lambda)H processes to elementary section 1H(e,e K+)Lambda free proton, measured during same experiment.
A large data set of charged-pion (pi+/-) electroproduction from both hydrogen and deuterium targets has been obtained spanning the low-energy residual-mass region. These conclusively show onset quark-hadron duality phenomenon, as predicted for high-energy hadron electroproduction. We construct several ratios these to exhibit relation this phenomenon factorization ansatz electron-quark scattering subsequent quark-->pion production mechanisms.
The generalized Baldin sum rule for virtual photon scattering, the unpolarized analogy of Gerasimov-Drell-Hearn integral provides an important way to investigate transition between perturbative QCD and hadronic descriptions nucleon structure. This requires integration structure function ${F}_{1}$, which until recently had not been measured at low ${Q}^{2}$ large $x$, i.e., in resonance region. work uses new data from inclusive electron-proton scattering region obtained Jefferson Lab,...