A. Ahmidouch
A5046480810- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- Nuclear physics research studies
- High-Energy Particle Collisions Research
- Nuclear Physics and Applications
- Superconducting Materials and Applications
- Advanced NMR Techniques and Applications
- Atomic and Subatomic Physics Research
- Particle Accelerators and Free-Electron Lasers
- Quantum, superfluid, helium dynamics
- Particle Detector Development and Performance
- Atomic and Molecular Physics
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced Chemical Physics Studies
- Particle accelerators and beam dynamics
- Radiation Detection and Scintillator Technologies
- Magnetic confinement fusion research
- High-pressure geophysics and materials
- Dark Matter and Cosmic Phenomena
- Scientific Research and Discoveries
- Advanced Data Storage Technologies
- Inorganic Fluorides and Related Compounds
- Medical Imaging Techniques and Applications
- Radiation Therapy and Dosimetry
- Neutrino Physics Research
North Carolina Agricultural and Technical State University
2013-2022
Tohoku University
2013
University of North Carolina at Chapel Hill
2011
Hampton University
1998-2007
Kent State University
1997-2007
University of Geneva
1990-2005
Thomas Jefferson National Accelerator Facility
1997-2001
Massachusetts Institute of Technology
1999
NCCR Chemical Biology - Visualisation and Control of Biological Processes Using Chemistry
1992-1997
University of Pennsylvania
1997
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 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 studied the electroproduction of $\ensuremath{\Delta}(1232)$ resonance via reaction $p({e,e}^{\ensuremath{'}}p){\ensuremath{\pi}}^{0}$ at four-momentum transfers ${Q}^{2}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}2.8\mathrm{and}4.0{\mathrm{GeV}}^{2}$. This is highest ${Q}^{2}$ for which exclusive has ever been observed. Decay angular distributions $\ensuremath{\Delta}\ensuremath{\rightarrow}p{\ensuremath{\pi}}^{0}$ were measured over a wide range barycentric energies covering...
We report the first measurement using a solid polarized target of neutron electric form factor G(n)(E) via d-->(e-->,e(')n)p. was determined from beam-target asymmetry in scattering longitudinally electrons deuterated ammonia ( 15ND3). The performed Hall C at Thomas Jefferson National Accelerator Facility quasifree kinematics with polarization perpendicular to momentum transfer. were detected magnetic spectrometer coincidence neutrons large angle segmented detector. find =...
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...
High precision measurements of the differential cross sections for π0 photoproduction at forward angles two nuclei, 12C and 208Pb, have been performed incident photon energies 4.9-5.5 GeV to extract π0→γγ decay width. The experiment was done Jefferson Lab using Hall B tagger a high-resolution multichannel calorimeter. width extracted by fitting measured recently updated theoretical models process. resulting value is Γ(π0→γγ)=7.82±0.14(stat)±0.17(syst) eV. With 2.8% total uncertainty, this...
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...
An experiment with a newly developed high-resolution kaon spectrometer (HKS) and scattered electron novel configuration was performed in Hall C at Jefferson Lab (JLab). The ground state of neutron-rich hypernucleus, He 7 Lambda, observed for the first time (e,e'K+) reaction an energy resolution ~0.6 MeV. This is best reported to date hypernuclear spectroscopy. he Lambda binding supplies last missing information A=7, T=1 iso-triplet, providing new input charge symmetry breaking (CSB) effect...
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...
Tensor polarization observables ( t20, t21, and t22) have been measured in elastic electron-deuteron scattering for six values of momentum transfer between 0.66 1.7(GeV/c)2. The experiment was performed at the Jefferson Laboratory Hall C using electron High Momentum Spectrometer, a specially designed deuteron magnetic channel recoil polarimeter POLDER. new data determine to much larger Q2 charge form factors GC GQ. They are good agreement with relativistic calculations disagree perturbative...
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...
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...
The first measurements of the differential cross section for d(gamma,p)n reaction up to 4.0 GeV were performed at Continuous Electron Beam Accelerator Facility (CEBAF) Jefferson Lab. We report sections proton center-of-mass angles 36, 52, 69 and 89 degrees. These results are in reasonable agreement with previous lower energy. degree data show constituent-counting-rule behavior photon 36 52 disagree counting rule behavior. quantum chromodynamics (QCD) model nuclear reactions involving reduced...
The differential cross section for the process p(e,e′p)η has been measured at Q2=2.4 and 3.6 (GeV/c)2 center-of-mass energies encompassing S11(1535) resonance. latter point is highest-Q2 exclusive measurement of this to date. resonance width helicity-1/2 transition amplitude are extracted from data, evidence possible onset scaling in reaction shown. A lower bound ≈0.45 placed on S11(1535)→pη branching fraction.Received 2 March 1999DOI:https://doi.org/10.1103/PhysRevD.60.052004©1999 American...
We report the results from a systematic study of quasielastic $(e,{e}^{\ensuremath{'}}p)$ reaction on $^{12}\mathrm{C},\phantom{\rule{0.5em}{0ex}}^{56}\mathrm{Fe}$, and $^{197}\mathrm{Au}$ performed at Jefferson Lab. have measured nuclear transparency extracted spectral functions (corrected for radiation) over ${Q}^{2}$ range $0.64--3.25\phantom{\rule{0.5em}{0ex}}{(\text{GeV}∕c)}^{2}$ all three nuclei. In addition, we separated longitudinal transverse 0.64...
The ( ${e,e}^{\ensuremath{'}}p$) reaction was studied on targets of C, Fe, and Au at momentum transfers squared ${Q}^{2}$ 0.6, 1.3, 1.8, $3.3{\mathrm{GeV}}^{2}$ in a region kinematics dominated by quasifree electron-proton scattering. Missing energy missing distributions are reasonably well described plane wave impulse approximation calculations with $A$ dependent corrections that measure the attenuation final state protons.
The quasielastic ${(e,e}^{\ensuremath{'}}p)$ reaction was studied on targets of deuterium, carbon, and iron up to a value momentum transfer ${Q}^{2}$ $8.1(\mathrm{GeV}{/c)}^{2}.$ A nuclear transparency determined by comparing the data calculations in plane-wave impulse approximation. dependence mass number investigated search for onset color phenomenon. We find no evidence within our range ${Q}^{2}.$ fit world's reflects energy free-proton--nucleon cross section.
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...
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...
Since the pioneering experiment, E89-009 studying hypernuclear spectroscopy using $(e,e^{\prime}K^+)$ reaction was completed, two additional experiments, E01-011 and E05-115, were performed at Jefferson Lab. These later experiments used a modified experimental design, "tilt method", to dramatically suppress large electromagnetic background, allowed for substantial increase in luminosity. Additionally, new kaon spectrometer, HKS (E01-011), electron HES, splitting magnet added produce...
The explicit breaking of the axial symmetry by quantum fluctuations gives rise to so-called anomaly. This phenomenon is solely responsible for decay neutral pion π0 into two photons (γγ), leading its unusually short lifetime. We precisely measured width Γ [Formula: see text] process. differential cross sections photoproduction at forward angles were on targets, carbon-12 and silicon-28, yielding text], where stat. denotes statistical uncertainty syst. systematic uncertainty. combined results...
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{...