M. Khandaker
A5006921024- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Nuclear physics research studies
- Atomic and Subatomic Physics Research
- Particle Accelerators and Free-Electron Lasers
- Advanced NMR Techniques and Applications
- Dark Matter and Cosmic Phenomena
- Atomic and Molecular Physics
- Particle Detector Development and Performance
- Nuclear Physics and Applications
- Quantum, superfluid, helium dynamics
- Medical Imaging Techniques and Applications
- Radiation Detection and Scintillator Technologies
- Superconducting Materials and Applications
- Advanced Chemical Physics Studies
- Particle accelerators and beam dynamics
- Electron and X-Ray Spectroscopy Techniques
- Cold Atom Physics and Bose-Einstein Condensates
- Neutrino Physics Research
- Photocathodes and Microchannel Plates
- High-pressure geophysics and materials
- Advanced X-ray Imaging Techniques
- Inorganic Fluorides and Related Compounds
- Astronomical and nuclear sciences
Norfolk State University
2014-2023
Idaho State University
2014-2023
Thomas Jefferson National Accelerator Facility
2001-2022
Istituto Nazionale di Fisica Nucleare, Sezione di Genova
2004-2022
Renewable Energy Systems (United States)
2021
University of York
2020-2021
North Carolina Agricultural and Technical State University
2009-2019
Argonne National Laboratory
2015-2018
Institut National de Physique Nucléaire et de Physique des Particules
2018
Université Paris-Sud
2018
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.
In an exclusive measurement of the reaction gammad-->K(+)K(-)pn, a narrow peak that can be attributed to exotic baryon with strangeness S=+1 is seen in K(+)n invariant mass spectrum. The at 1.542+/-0.005 GeV/c(2) measured width 0.021 FWHM, which largely determined by experimental resolution. statistical significance (5.2+/-0.6)sigma. and observed are consistent recent reports other groups.
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...
The atomic nucleus is composed of two different kinds fermions, protons and neutrons. If the neutrons did not interact, Pauli exclusion principle would force majority fermions (usually neutrons) to have a higher average momentum. Our high-energy electron scattering measurements using 12C, 27Al, 56Fe 208Pb targets show that, even in heavy neutron-rich nuclei, short-range interactions between form correlated high-momentum neutron-proton pairs. Thus, greater probability than momentum Fermi This...
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 the first results of beam-spin asymmetry measured in reaction $\stackrel{\ensuremath{\rightarrow}}{e}p\ensuremath{\rightarrow}\mathrm{ep}\ensuremath{\gamma}$ at a beam energy 4.25 GeV. A large with $\mathrm{sin}\ensuremath{\varphi}$ modulation is observed, as predicted for interference term deeply virtual compton scattering (DVCS) and Bethe-Heitler process. The amplitude this...
The ratios of inclusive electron scattering cross sections 4He, 12C, and 56Fe to 3He have been measured at 1<xB<3. At Q2>1.4 GeV2, the exhibit two separate plateaus, 1.5<xB<2 xB>2.25. This pattern is predicted by models that include 2- 3-nucleon short-range correlations (SRC). Relative A=3, per-nucleon probabilities SRC are 2.3, 3.1, 4.4 times larger for A=4, 12, 56. first measurement in nuclei.Received 16 August 2005DOI:https://doi.org/10.1103/PhysRevLett.96.082501©2006 American Physical Society
We present results on the electroexcitation of low mass resonances Delta(1232)P33, N(1440)P11, N(1520)D13, and N(1535)S11 in a wide range Q2. The were obtained comprehensive analysis JLab-CLAS data differential cross sections, longitudinally polarized beam asymmetries, longitudinal target beam-target asymmetries for pion electroproduction off proton. analysed using two conceptually different approaches, fixed-t dispersion relations unitary isobar model, allowing us to draw conclusions model...
Models of baryon structure predict a small quadrupole deformation the nucleon due to residual tensor forces between quarks or distortions from pion cloud. Sensitivity quark versus degrees freedom occurs through Q2 dependence magnetic (M1+), electric (E1+), and scalar (S1+) multipoles in gamma*p-->Delta(+)-->p pi(0) transition. We report new experimental values for ratios E(1+)/M(1+) S(1+)/M(1+) over range = 0.4-1.8 GeV2, extracted precision p(e,e(')p)pi(0) data using truncated multipole...
Cross-sections and recoil polarizations for the reactions gamma + p --> K^+ Lambda Sigma^0 have been measured with high statistics good angular coverage center-of-mass energies between 1.6 2.3 GeV. In K^+Lambda channel we confirm a structure near W=1.9 GeV at backward kaon angles, but our data shows more complex s- u- resonance than previously seen. This is present forward angles not central its position width change angle, indicating that one playing role. Rising back-angle cross sections...
We present measurements of the differential cross section and $\ensuremath{\Lambda}$ recoil polarization for $\ensuremath{\gamma}p\ensuremath{\rightarrow}{K}^{+}\ensuremath{\Lambda}$ reaction made using CLAS detector at Jefferson Lab. These cover center-of-mass energy range from $1.62$ to $2.84$ GeV a wide ${K}^{+}$ production angles. Independent analyses were performed ${K}^{+}p{\ensuremath{\pi}}^{\ensuremath{-}}$ ${K}^{+}p$ (missing ${\ensuremath{\pi}}^{\ensuremath{-}}$) final-state...
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 transition helicity amplitudes from the proton ground state to $P_{11}(1440)$ and $D_{13}(1520)$ excited states ($\gamma_{v}pN^*$ electrocouplings) were determined analysis of nine independent one-fold differential $\pi^{+} \pi^{-} p$ electroproduction cross sections off a target, taken with CLAS at photon virtualities 0.25\enskip {\rm GeV$^{2}$} $<$ $Q^{2}$ 0.60 \enskip GeV$^{2}$}. phenomenological reaction model was employed for separation resonant non-resonant contributions final...
Unpolarized and beam-polarized fourfold cross sections (d^{4}σ/dQ^{2}dx_{B}dtdϕ) for the ep→e^{'}p^{'}γ reaction were measured using CLAS detector 5.75-GeV polarized electron beam of Jefferson Lab accelerator, 110 (Q^{2},x_{B},t) bins over widest phase space ever explored in valence-quark region. Several models generalized parton distributions (GPDs) describe data well at most our kinematics. This increases confidence that we understand GPD H, expected to be dominant contributor these...
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...
New high-precision measurements of $p(\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\gamma}},\ensuremath{\pi})$ and $p(\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\gamma}},\ensuremath{\gamma})$ cross sections beam asymmetries have been combined with other polarization ratios in a simultaneous analysis both reactions. Compton scattering has provided two important new constraints on the photopion amplitude. The $E2/M1$ mixing ratio for $N\ensuremath{\rightarrow}\ensuremath{\Delta}$...
We report the first evidence for a nonzero beam-spin azimuthal asymmetry in electroproduction of positive pions deep-inelastic kinematic region. Data reaction $e\stackrel{\ensuremath{\rightarrow}}{p}{e}^{\ensuremath{'}}{\ensuremath{\pi}}^{+}X$ have been obtained using polarized electron beam 4.3 GeV with CEBAF Large Acceptance Spectrometer at Thomas Jefferson National Accelerator Facility. The amplitude $\mathrm{sin}\ensuremath{\varphi}$ modulation increases momentum pion relative to virtual...
The electric form factor of the neutron was determined from studies reaction ${}^{3}\stackrel{\ensuremath{\rightarrow}}{\mathrm{He}}(\stackrel{\ensuremath{\rightarrow}}{e},{e}^{\ensuremath{'}}n)pp$ in quasielastic kinematics Hall A at Jefferson Lab. Longitudinally polarized electrons were scattered off a target which nuclear polarization oriented perpendicular to momentum transfer. detected magnetic spectrometer coincidence with neutrons that registered large-solid-angle detector. More than...
Differential cross sections for the reaction $\gamma p \to n \pi^+$ have been measured with CEBAF Large Acceptance Spectrometer (CLAS) and a tagged photon beam energies from 0.725 to 2.875 GeV. Where available, results obtained here compare well previously published reaction. Agreement SAID MAID analyses is found below 1 The present set of has incorporated into database, exploratory fits made up 2.7 Resonance couplings extracted compared previous determinations. With addition these world...