G. Feldman
A5045224943- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- Nuclear physics research studies
- High-Energy Particle Collisions Research
- Nuclear Physics and Applications
- Information Technology Governance and Strategy
- Atomic and Subatomic Physics Research
- Nuclear reactor physics and engineering
- Experimental Learning in Engineering
- Superconducting Materials and Applications
- Atomic and Molecular Physics
- Advanced NMR Techniques and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- ERP Systems Implementation and Impact
- Advanced Chemical Physics Studies
- Smart Cities and Technologies
- Science Education and Pedagogy
- Innovative Teaching Methods
- Particle Detector Development and Performance
- Quantum, superfluid, helium dynamics
- Outsourcing and Supply Chain Management
- Dark Matter and Cosmic Phenomena
- Nuclear Materials and Properties
- Advanced X-ray Imaging Techniques
- Particle accelerators and beam dynamics
Birmingham City University
2015-2024
George Washington University
2013-2023
ETH Zurich
2019
University of Connecticut
2007-2013
Harvard University Press
2010-2011
Systems Planning and Analysis (United States)
2007
California State University, Dominguez Hills
2007
University of California, Los Angeles
2007
Campbell Collaboration
2007
Mayo Clinic
2007
High-statistics cross sections for the reactions gamma + p --> K^+ Lambda and Sigma^0 have been measured using CLAS at Jefferson Lab center-of-mass energies W between 1.6 2.53 GeV, -0.85 < cos theta_{K^+}^{c.m.}< +0.95. In channel we confirm a resonance-like structure near W=1.9 GeV backward kaon angles. The position width of this change with angle, indicating that more than one resonance is likely playing role. forward angles all well described by t-channel scaling characteristic Regge...
The beam-spin asymmetries in the hard exclusive electroproduction of photons on proton ($\stackrel{\ensuremath{\rightarrow}}{e}p\ensuremath{\rightarrow}ep\ensuremath{\gamma}$) were measured over a wide kinematic range and with high statistical accuracy. These result from interference Bethe-Heitler process deeply virtual Compton scattering. Over whole (${x}_{B}$ 0.11 to 0.58, ${Q}^{2}$ 1 $4.8\text{ }\text{ }{\mathrm{GeV}}^{2}$, $\ensuremath{-}t$ 0.09 $1.8\text{ }{\mathrm{GeV}}^{2}$),...
Spin transfer from circularly polarized real photons to recoiling hyperons has been measured for the reactions $\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\gamma}}+p\ensuremath{\rightarrow}{K}^{+}+\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\Lambda}}$ and $\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\gamma}}+p\ensuremath{\rightarrow}{K}^{+}+{\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\Sigma}}}^{0}$. The data were obtained using CEBAF Large Acceptance Spectrometer (CLAS)...
Differential cross sections for gammap-->etap have been measured with tagged real photons incident photon energies from 0.75 to 1.95 GeV. Mesons were identified by missing mass reconstruction using kinematical information protons scattered in the production process. The data provide first extensive angular distribution measurements process above W=1.75 Comparison preliminary results a constituent quark model support suggestion that third S11 resonance approximately 1.8 GeV couples etaN channel.
The cross section for the reaction ep-->e(')ppi(+)pi(-) was measured in resonance region 1.4<W<2.1 GeV and 0.5<Q2<1.5 GeV(2)/c(2) using CLAS detector at Jefferson Laboratory. data show resonant structures not visible previous experiments. comparison of our to a phenomenological prediction available information on N(*) Delta states shows an evident discrepancy. A better description is obtained either by sizable change properties P13(1720) or introducing new baryon state, reported published analyses.
The longitudinal target-spin asymmetry ${A}_{\mathrm{UL}}$ for the exclusive electroproduction of high-energy photons was measured first time in $e\stackrel{\ensuremath{\rightarrow}}{p}\ensuremath{\rightarrow}{e}^{\ensuremath{'}}p\ensuremath{\gamma}$. data have been accumulated at JLab with CLAS spectrometer using 5.7 GeV electrons and a longitudinally polarized ${\mathrm{NH}}_{3}$ target. A significant azimuthal angular dependence observed, resulting from interference deeply virtual Compton...
Splitting of the giant dipole resonance built on excited states Er nuclei, observed in continuum $\ensuremath{\gamma}$-ray spectra from $^{12}\mathrm{C}$ + $^{148}\mathrm{Sm}$ and $^{154}\mathrm{Sm}$ reactions, reveals persistence prolate, ground-state-like deformation at elevated temperature $T\ensuremath{\sim}1$ MeV spins $I=0 \mathrm{to} 25\ensuremath{\hbar}$.
We report a new measurement of the exclusive electroproduction reaction ${\ensuremath{\gamma}}^{*}p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}p$ to explore evolution from soft nonperturbative physics hard processes via ${Q}^{2}$ dependence magnetic (${M}_{1+}$), electric (${E}_{1+}$), and scalar (${S}_{1+}$) multipoles in $N\ensuremath{\rightarrow}\ensuremath{\Delta}$ transition. 9000 differential cross section data points cover $W$ threshold $1.4\text{ }\text{ }\mathrm{GeV}/{c}^{2}$,...
A search for the Θ+ in reaction γd→pK−K+n was completed using CLAS detector at Jefferson Lab. study of same reaction, published earlier, reported observation a narrow resonance. The present experiment, with more than 30 times integrated luminosity our earlier measurement, does not show any evidence pentaquark angle-integrated upper limit on production mass range 1.52–1.56 GeV/c2 γd→pK−Θ+ is 0.3 nb (95% C.L.). This depends assumptions made and angular distribution production. Using Λ(1520) as...
Differential cross sections for the reaction $\gamma p \to \pi^0$ have been measured with CEBAF Large Acceptance Spectrometer (CLAS) and a tagged photon beam energies from 0.675 to 2.875 GeV. The results reported here possess greater accuracy in absolute normalization than previous measurements. They disagree recent CB-ELSA measurements process at forward scattering angles. Agreement SAID MAID fits is found below 1 present set of has incorporated into database, exploratory extended 3...
For developing smart cities, it is necessary to integrate all components of a city as system systems.This facilitated by urban computing technology address the complexity providing adequate services citizens through various sectors/systems.Since business processes across sectors/systems should be aligned with objectives computing, Business Process Change (BPC) also significant prerequisite systems integration for Smart City Development (SCD).However, there limited research on understanding...
The photoproduction of vector mesons on various nuclei has been studied using the CLAS detector at Jefferson Laboratory. mesons, ρ, ω, and ϕ, are observed via their decay to e+e−, in order reduce effects final-state interactions nucleus. Of particular interest possible in-medium properties ρ meson. mass spectrum is extracted from data nuclei, 2H, C, Fe, Ti. We observe no significant shift some broadening consistent with expected collisional for meson.Received 20 July...
The helicity amplitudes of the electroexcitation Roper resonance are extracted for 1.7 < Q2 4.5 GeV2 from recent high precision JLab-CLAS cross section and longitudinally polarized beam asymmetry data pi+ electroproduction on protons at W=1.15-1.69 GeV. analysis is made using two approaches, dispersion relations a unitary isobar model, which give consistent results. It found that transverse amplitude A_{1/2} gamma* p -> N(1440)P11 transition, large negative Q2=0, becomes positive ~ 2 GeV2,...
The light vector mesons ($\rho$, $\omega$, and $\phi$) were produced in deuterium, carbon, titanium, iron targets a search for possible in-medium modifications to the properties of $\rho$ meson at normal nuclear densities zero temperature. detected with CEBAF Large Acceptance Spectrometer (CLAS) via their decays $e^{+}e^{-}$. rare leptonic decay was chosen reduce final-state interactions. A combinatorial background subtracted from invariant mass spectra using well-established event-mixing...
The exclusive electroproduction process $\vec{e}p \to e^\prime n \pi^+$ was measured in the range of photon virtuality $Q^2 = 1.7 - 4.5 \rm{GeV^2}$, and invariant mass for $n\pi^+$ system $W 1.15 \rm{GeV}$ using CEBAF Large Acceptance Spectrometer. For first time, these kinematics are probed $\pi^+$ production from protons with nearly full coverage azimuthal polar angles center-of-mass system. channel has particular sensitivity to isospin 1/2 excited nucleon states, together $p\pi^0$ final...
The electromagnetic polarizabilities of the nucleon are fundamental properties that describe its response to external electric and magnetic fields. They can be extracted from Compton-scattering data-and have been, with good accuracy, in case proton. In contradistinction, information for neutron requires use Compton scattering nuclear targets. Here, we report a new measurement elastic photon deuterium using quasimonoenergetic tagged photons at MAX IV Laboratory Lund, Sweden. These first data...
Continuum \ensuremath{\gamma}-ray spectra from decays of $^{63}\mathrm{Cu}$ formed at initial excitation energies 22.5 to 77.4 MeV and maximum spin up 40\ensuremath{\Elzxh}, using $^{4}\mathrm{Co}$, $^{6}$Li${+\mathrm{}}^{57}$Fe, $^{12}$C${+\mathrm{}}^{51}$V, $^{18}$O${+\mathrm{}}^{45}$Sc entrance channels, have been measured analyzed. The parameters the giant dipole resonance strength function extracted a statistical code in nonlinear least-squares fitting routine. Except for cases...
The $\mathit{ep}\ensuremath{\rightarrow}{e}^{'}{\ensuremath{\pi}}^{+}n$ reaction was studied in the first and second nucleon resonance regions $0.25$ GeV${}^{2}<{Q}^{2}<0.65$ GeV${}^{2}$ range by use of CLAS detector at Thomas Jefferson National Accelerator Facility. For time, to our knowledge, absolute cross sections were measured, covering nearly full angular hadronic center-of-mass frame. We extracted structure functions...
We report measurements of the exclusive electroproduction ${K}^{+}\ensuremath{\Lambda}$ and ${K}^{+}{\ensuremath{\Sigma}}^{0}$ final states from a proton target using Continuous Electron Beam Accelerator Facility (CEBAF) large-acceptance spectrometer (CLAS) detector at Thomas Jefferson National Facility. The separated structure functions ${\ensuremath{\sigma}}_{T},{\ensuremath{\sigma}}_{L},{\ensuremath{\sigma}}_{\mathit{TT}}$, ${\ensuremath{\sigma}}_{\mathit{LT}}$ were extracted...
Differential cross sections for the reaction $\ensuremath{\gamma}p\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}p$ have been measured with CLAS spectrometer and a tagged photon beam energies from 1.527 to 2.227 GeV. The results reported here possess much greater accuracy than previous measurements. Analyses of these data suggest first time coupling ${\ensuremath{\eta}}^{\ensuremath{'}}N$ channel both ${S}_{11}(1535)$ ${P}_{11}(1710)$ resonances, known couple strongly...
The spin structure functions g_1 for the proton and deuteron have been measured over a wide kinematic range in x Q2 using 1.6 5.7 GeV longitudinally polarized electrons incident upon NH_3 ND_3 targets at Jefferson Lab. Scattered were detected CEBAF Large Acceptance Spectrometer, 0.05 < Q^2 5 GeV^2 W 3 GeV. first moments of are presented -- both negative slope low Q^2, as predicted by extended Gerasimov-Drell-Hearn sum rule. result generalized forward polarizability gamma_0^p is also...
This paper describes research on a classification of physics problems in the context introductory courses. classification, called Taxonomy Introductory Physics Problems (TIPP), relates to cognitive processes required solve them. TIPP was created order design educational objectives, develop assessments that can evaluate individual component problem-solving process, and guide curriculum courses, specifically within ``thinking-skills'' curriculum. Moreover, enables future education researchers...
Beam-helicity asymmetries for the two-pion-photoproduction reaction gamma + p --> pi+ pi- have been studied first time in resonance region center-of-mass energies between 1.35 GeV and 2.30 GeV. The experiment was performed at Jefferson Lab with CEBAF Large Acceptance Spectrometer using circularly polarized tagged photons incident on an unpolarized hydrogen target. Beam-helicity-dependent angular distributions of final-state particles were measured. large cross-section exhibit strong...