A5000051126- 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
- Quantum, superfluid, helium dynamics
- Atomic and Subatomic Physics Research
- Particle Detector Development and Performance
- Nuclear Physics and Applications
- Quantum chaos and dynamical systems
- Radiation Detection and Scintillator Technologies
- Particle accelerators and beam dynamics
- Superconducting Materials and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Advanced NMR Techniques and Applications
- Dark Matter and Cosmic Phenomena
- Photocathodes and Microchannel Plates
- Atomic and Molecular Physics
- Advanced Algebra and Geometry
- Cold Fusion and Nuclear Reactions
- Gyrotron and Vacuum Electronics Research
- Advanced Data Storage Technologies
- Radiation Therapy and Dosimetry
- Spectroscopy and Quantum Chemical Studies
- Advanced Semiconductor Detectors and Materials
Thomas Jefferson National Accelerator Facility
2010-2020
North Carolina Agricultural and Technical State University
2019
Kyungpook National University
2009-2017
Old Dominion University
2014-2017
Temple University
2017
Temple College
2017
Federico Santa María Technical University
2017
Florida State University
2013-2016
University of South Carolina
2009-2015
Northern Illinois University
2015
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...
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...
Proton recoil polarization was measured in the quasielastic 4He(e,e'p)3H reaction at Q{2}=0.8 and 1.3 (GeV/c){2} with unprecedented precision. The polarization-transfer coefficients are found to differ from those of 1H(e,e'p) reaction, contradicting a relativistic distorted-wave approximation favoring either inclusion medium-modified proton form factors predicted by quark-meson coupling model or spin-dependent charge-exchange final-state interaction. For first time, ratio is studied as...
Because of their long lifetimes, the ω and ϕ mesons are ideal candidates for study possible modifications in-medium meson-nucleon interaction through absorption inside nucleus. During E01-112 experiment at Thomas Jefferson National Accelerator Facility, were photoproduced from 2H, C, Ti, Fe, Pb targets. This Letter reports first measurement ratio nuclear transparencies e+e- channel. The ratios indicate larger widths compared with what have been reported in other reaction channels. meson is...
Single-beam, single-target, and double-spin asymmetries for hard exclusive photon production on the proton $\vec{e}\vec{p} \to e' p'\gamma$ are presented. The data were taken at Jefferson Lab using CLAS detector a longitudinally polarized ${}^{14}$NH$_3$ target. three measured in 165 4-dimensional kinematic bins, covering widest range ever explored simultaneously beam target-polarization observables valence quark region. dependences of obtained discussed compared to predictions models...
Differential cross sections of the exclusive process $ep\ensuremath{\rightarrow}{e}^{\ensuremath{'}}{\ensuremath{\pi}}^{+}n$ were measured with good precision in range photon virtuality ${Q}^{2}=1.8--4.5$ ${\mathrm{GeV}}^{2}$ and invariant mass ${\ensuremath{\pi}}^{+}n$ final state $W=1.6--2.0$ GeV using Continuous Electron Beam Accelerator Facility Large Acceptance Spectrometer. Data collected nearly complete coverage azimuthal polar angles $n{\ensuremath{\pi}}^{+}$ center-of-mass system....
We present the final results for deuteron spin structure functions obtained from full data set collected with Jefferson Lab's CLAS in 2000-2001. Polarized electrons energies of 1.6, 2.5, 4.2 and 5.8 GeV were scattered ($^{15}$ND$_3$) targets, dynamically polarized along beam direction, detected CLAS. From measured double asymmetry, virtual photon absorption asymmetry $A_1^d$ function $g_1^d$ extracted over a wide kinematic range (0.05 GeV$^2 < Q^2 <$ 5 GeV$^2$ 0.9 $< W 3 GeV). use an...
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...
An event-based partial wave analysis (PWA) of the reaction $\ensuremath{\gamma}p\ensuremath{\rightarrow}p\ensuremath{\omega}$ has been performed on a high-statistics dataset obtained using CLAS at Jefferson Lab for center-of-mass energies from threshold up to 2.4 GeV. This benefits access world's first high-precision spin-density matrix element measurements, available PWA through decay distribution...
We report the first observation of line shape $\Lambda(1405)$ from electroproduction, and show that it is not a simple Breit-Wigner resonance. Electroproduction $K^+ \Lambda(1405)$ off proton was studied by using data CLAS at Jefferson Lab in range $1.0<Q^2<3.0$ (GeV/c)$^2$. The analysis utilized decay channels $\Sigma^+ \pi^-$ $p \pi^0$ $\Sigma^+$. Neither standard (PDG) resonance parameters, nor free parameters fitting to single represent shape. In our fits, corresponds approximately...
We report on the first measurement of cross sections for exclusive deeply virtual pion electroproduction off proton, $e p \to e^\prime n \pi^+$, above resonance region at backward center-of-mass angles. The $\varphi^*_{\pi}$-dependent were measured, from which we extracted three combinations structure functions proton. Our results are compatible with calculations based nucleon-to-pion transition distribution amplitudes (TDAs) and shed new light nucleon structure.
We have measured the $^{3}\mathrm{He}(e,{e}^{\ensuremath{'}}pp)n$ reaction at an incident energy of 4.7 GeV over a wide kinematic range. identified spectator correlated $pp$ and $pn$ nucleon pairs by using cuts their relative total momentum distributions. This is first measurement ratio to as function pair ${p}_{\mathrm{tot}}$. For momenta between 0.3 $0.5\text{ }\text{ }\mathrm{GeV}/c$, very small low ${p}_{\mathrm{tot}}$ rises approximately 0.5 large shows dominance tensor central...
We report measurements of the exclusive electroproduction $K^+\Lambda$ and $K^+\Sigma^0$ final states from an unpolarized proton target using CLAS detector at Thomas Jefferson National Accelerator Facility. The separated structure functions $\sigma_U$, $\sigma_{LT}$, $\sigma_{TT}$, $\sigma_{LT'}$ were extracted $\Phi$-dependent differential cross sections acquired with a longitudinally polarized 5.499 GeV electron beam. data span broad range momentum transfers $Q^2$ 1.4 to 3.9 GeV$^2$,...
The exclusive electroproduction of $\pi^+$ above the resonance region was studied using $\rm{CEBAF}$ Large Acceptance Spectrometer ($\rm{CLAS}$) at Jefferson Laboratory by scattering a 6 GeV continuous electron beam off hydrogen target. large acceptance and good resolution $\rm{CLAS}$, together with high luminosity, allowed us to measure cross section for $\gamma^* p \to n \pi^+$ process in 140 ($Q^2$, $x_B$, $t$) bins: $0.16<x_B<0.58$, 1.6 GeV$^2<$$Q^2$$<4.5$ GeV$^2$ 0.1 GeV$^2<$$-t$$<5.3$...
We present a search for ten baryon number violating decay modes of $\mathrm{\ensuremath{\Lambda}}$ hyperons using the CLAS detector at Jefferson Laboratory. Nine these result in single meson and lepton final state ($\mathrm{\ensuremath{\Lambda}}\ensuremath{\rightarrow}m\ensuremath{\ell}$) conserve either sum or difference ($B\ifmmode\pm\else\textpm\fi{}L$). The tenth mode ($\mathrm{\ensuremath{\Lambda}}\ensuremath{\rightarrow}\overline{p}{\ensuremath{\pi}}^{+}$) represents two units no...
The first high-statistics cross sections for the reactions $\gamma p \to K^{*+} \Lambda$ and \Sigma^0$ were measured using CLAS detector at photon energies between threshold 3.9 GeV Thomas Jefferson National Accelerator Facility. Differential are presented over full range of center-of-mass angles, $\theta^{CM}_{K^{*+}}$, then fitted to Legendre polynomials extract total section. Results $K^{*+}\Lambda$ final state compared with two different calculations in an isobar a Regge model,...
The target and double spin asymmetries of the exclusive pseudoscalar channel e→p→→epπ0 were measured for first time in deep-inelastic regime using a longitudinally polarized 5.9 GeV electron beam proton at Jefferson Lab with CEBAF Large Acceptance Spectrometer (CLAS). data collected over large kinematic phase space divided into 110 four-dimensional bins Q2, xB, −t ϕ. values asymmetry moments clearly indicate substantial contribution to structure functions from transverse virtual photon...
We report the first extraction of pion-nucleon multipoles near production threshold for $n{\ensuremath{\pi}}^{+}$ channel at relatively high momentum transfer (${Q}^{2}$ up to 4.2 ${\mathrm{GeV}}^{2}$). The dominance $s$-wave transverse multipole (${E}_{0+}$), expected in this region, allowed us access generalized form factor ${G}_{1}$ within light-cone sum-rule (LCSR) framework as well axial ${G}_{A}$. data analyzed work were collected by nearly $4\ensuremath{\pi}$ CEBAF Large Acceptance...
We have measured the induced polarization of ${\Lambda}(1116)$ in reaction $ep\rightarrow e'K^+{\Lambda}$, detecting scattered $e'$ and $K^+$ final state along with proton from decay $\Lambda\rightarrow p\pi^-$.The present study used CEBAF Large Acceptance Spectrometer (CLAS), which allowed for a large kinematic acceptance invariant energy $W$ ($1.6\leq W \leq 2.7$ GeV) covered full range kaon production angle at an average momentum transfer $Q^2=1.90$ GeV$^2$.In this experiment 5.50 GeV...
The CLAS detector was used to obtain the first ever measurement of electromagnetic decay ${\ensuremath{\Sigma}}^{*+}(1385)$ from reaction $\ensuremath{\gamma}p\ensuremath{\rightarrow}{K}^{0}{\ensuremath{\Sigma}}^{*+}(1385)$. A real photon beam with a maximum energy 3.8 GeV incident on liquid-hydrogen target, resulting in photoproduction kaon and ${\ensuremath{\Sigma}}^{*}$ hyperon. Kinematic fitting separate channel background processes. algorithm exploited new method kinematically fit...
The three-dimensional picture of quarks and gluons in the proton is set to be revealed through Deeply virtual Compton scattering while a critically important puzzle one-dimensional remains, namely, origins EMC effect. Incoherent nuclear DVCS, i.e. DVCS on nucleon inside nucleus, can reveal 3D partonic structure bound shed new light However, Fermi motion struck nucleon, off-shell effects final-state interactions (FSIs) complicate this parton level interpretation. We propose here measurement...
Background: The deuteron plays a pivotal role in nuclear and hadronic physics, as both the simplest bound multinucleon system an effective neutron target. Quasielastic electron scattering on is benchmark reaction to test our understanding of structure properties interactions two nucleons deuteron.Purpose: experimental data presented here can be used state-of-the-art models two-nucleon interaction final state after two-body breakup deuteron. Focusing polarization degrees freedom, we gain...