B. Morrison
A5063160513- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Nuclear physics research studies
- High-Energy Particle Collisions Research
- Atomic and Subatomic Physics Research
- Nuclear Physics and Applications
- Dark Matter and Cosmic Phenomena
- Particle Accelerators and Free-Electron Lasers
- Quantum, superfluid, helium dynamics
- Gamma-ray bursts and supernovae
- Solar and Space Plasma Dynamics
- Speech and Audio Processing
- Superconducting Materials and Applications
- Radioactive Decay and Measurement Techniques
- Advanced Chemical Physics Studies
- Advanced NMR Techniques and Applications
- Atomic and Molecular Physics
- Radiation Therapy and Dosimetry
- Acoustic Wave Resonator Technologies
- RFID technology advancements
- Inorganic Fluorides and Related Compounds
Arizona State University
2009-2020
North Carolina Agricultural and Technical State University
2019
Hampton University
2012
Campbell Collaboration
2012
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...
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...
High-statistics differential cross sections for the reactions $\ensuremath{\gamma}p\ensuremath{\rightarrow}p\ensuremath{\eta}$ and $\ensuremath{\gamma}p\ensuremath{\rightarrow}p{\ensuremath{\eta}}^{'}$ have been measured using CEBAF large acceptance spectrometer (CLAS) at Jefferson Lab center-of-mass energies from near threshold up to 2.84 GeV. The ${\ensuremath{\eta}}^{'}$ results are most precise date provide largest energy angular coverage. $\ensuremath{\eta}$ measurements extend range of...
We report the first measurement of transverse momentum dependence double-spin asymmetries in semi-inclusive production pions deep-inelastic scattering off longitudinally polarized proton. Data have been obtained using a electron beam 5.7 GeV with CLAS detector at Jefferson Lab (JLab). Modulations single spin over azimuthal angle between lepton and hadron planes ϕ measured wide kinematic range Bjorken x virtual photon squared four-momentum Q2. A significant nonzero sin2ϕ asymmetry was...
High-statistics measurements of differential cross sections and recoil polarizations for the reaction $\gamma p \rightarrow K^+ \Sigma^0$ have been obtained using CLAS detector at Jefferson Lab. We cover center-of-mass energies ($\sqrt{s}$) from 1.69 to 2.84 GeV, with an extensive coverage in $K^+$ production angle. Independent were made $K^{+}p\pi^{-}$($\gamma$) $K^{+}p$($\pi^-, \gamma$) final-state topologies, found exhibit good agreement. Our show agreement earlier CLAS, SAPHIR LEPS...
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...
We report on the first measurement of F2 structure function neutron from semi-inclusive scattering electrons deuterium, with low-momentum protons detected in backward hemisphere. Restricting momentum spectator to < 100 MeV and their angles degrees relative transfer allows an interpretation process terms nearly on-shell neutrons. The F2n data collected cover nucleon resonance deep-inelastic regions over a wide range Bjorken x for 0.65 Q2 4.52 GeV2, uncertainties nuclear corrections estimated...
High-statistics differential cross sections and spin density matrix elements for the reaction gamma p -> omega have been measured using CLAS at Jefferson Lab center-of-mass (CM) energies from threshold up to 2.84 GeV. Results are reported in 112 10-MeV wide CM energy bins, each subdivided into cos(theta_CM) bins of width 0.1. These most precise extensive photoproduction measurements date. A number prominent structures clearly present data. Many these not previously observed due limited...
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...
Results are presented for the first measurement of double-polarization helicity asymmetry E $η$ photoproduction reaction $γp \rightarrow ηp$. Data were obtained using FROzen Spin Target (FROST) with CLAS spectrometer in Hall B at Jefferson Lab, covering a range center-of-mass energy W from threshold to 2.15 GeV and large polar angle. As an initial application these data, results have been incorporated into Jülich model examine case existence narrow $N^*$ resonance between 1.66 1.70 GeV. The...
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...
Received 30 April 2012DOI:https://doi.org/10.1103/PhysRevLett.108.199902© 2012 American Physical Society
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...
The electromagnetic decay $\Sigma^0(1385) \to \Lambda \gamma$ was studied using the CLAS detector at Thomas Jefferson National Accelerator Facility. A real photon beam with a maximum energy of 3.8 GeV incident on proton target, producing an exclusive final state $K^+\Sigma^{*0}$. We report widths ratio \Lambda\gamma$/ \Lambda\pi^0$ = $1.42 \pm 0.12(\text{stat})_{-0.07}^{+0.11}(\text{sys})$%. This is larger than most theoretical predictions by factors ranging from 1.5-3, but consistent only...
We have measured the differential cross section for $\ensuremath{\gamma}$$^{3}\mathrm{He}$$\ensuremath{\rightarrow}\ensuremath{\pi}{}^{+}t$ reaction. This reaction was studied using Continuous Electron Beam Accelerator Facility (CEBAF) Large Acceptance Spectrometer (CLAS) at Jefferson Lab. Real photons produced with Hall-B bremsstrahlung tagging system in energy range from 0.50 to 1.55 GeV were incident on a cryogenic liquid $^{3}\mathrm{He}$ target. The sections as function of photon-beam...
The two-body photodisintegration of $^4$He into a proton and triton has been studied using the CEBAF Large-Acceptance Spectrometer (CLAS) at Jefferson Laboratory. Real photons produced with Hall-B bremsstrahlung-tagging system in energy range from 0.35 to 1.55 GeV were incident on liquid target. This is first measurement above 0.4 GeV. differential cross sections for $\gamma$$^4$He$\to pt$ reaction have measured as function photon-beam proton-scattering angle, are compared latest model...
The cross section of atomic electron Compton scattering γ+e→γ′+e′ was measured in the 4.400–5.475 GeV photon beam energy region by PrimEx collaboration at Jefferson Lab with an accuracy 2.6% and less. results are consistent theoretical predictions that include next-to-leading order radiative corrections. measurements provide first high precision test this elementary QED process energies greater than 0.1 GeV.
The CLAS Collaboration provides a comment on the physics interpretation of results presented in paper published by M. Amaryan et al. regarding possible observation narrow structure mass spectrum photoproduction experiment.
In Ref. [1], the authors claim to observe a narrow structure in mass spectrum constructed from (pK_L) system using data CLAS detector. The interpretation of this structure given in [1] is as follows: “It may be due photoproduction Theta+ pentaquark or some unknown Sigma∗ resonance.” go on say that “it unlikely for observed This analysis was reviewed by Collaboration, following established procedures all papers, and did not receive approval. purpose Comment explain reasons why approved...
Polarization observables are an important tool for clarifying the nucleon resonance spectrum. No previous measurements double polarization asymmetries have been published η photoproduction. Double made at Jefferson Lab using a polarized photon beam and protons in frozen spin target (FROST). Data were taken during first running period of FROST CLAS detector with energies from 0.33 to 2.35 GeV. Preliminary results E observable eta meson photoproduction proton threshold above, along comparisons...
Polarization observables are vital for disentangling overlapping resonances in the baryon spectrum. Extensive data have been collected at Jefferson Lab Hall B with circularly and linearly polarized tagged photon beam incident on longitudinally protons provided by Frozen Spin Target (FROST). The focus of described work is η photoproduction, which acts as an "isospin filter", isolating N*(I = 1/2) resonances. Preliminary results double-polarization E G presented. There currently no these world...