F. J. Klein
A5090865094- 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
- Electron and X-Ray Spectroscopy Techniques
- Advanced X-ray Imaging Techniques
- Advanced NMR Techniques and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Photocathodes and Microchannel Plates
- Dark Matter and Cosmic Phenomena
- Medical Imaging Techniques and Applications
- Quantum, superfluid, helium dynamics
- Particle Detector Development and Performance
- Particle Accelerators and Free-Electron Lasers
- Radiation Detection and Scintillator Technologies
- Nuclear Physics and Applications
- Neutrino Physics Research
- Calibration and Measurement Techniques
- Astronomical and nuclear sciences
- High-pressure geophysics and materials
- Particle accelerators and beam dynamics
- Advanced Data Storage Technologies
- Experimental and Theoretical Physics Studies
- Laser-Plasma Interactions and Diagnostics
Catholic University of America
2013-2022
University of America
2012-2022
University of York
2021
North Carolina Agricultural and Technical State University
2019
George Washington University
2018
Carnegie Mellon University
2018
California State University, Dominguez Hills
2007-2018
Duke University
2018
Fermi National Accelerator Laboratory
2018
Canisius College
2018
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...
Total and differential cross sections for the reaction p(gamma,eta)p have been measured photon energies in range from 750 MeV to 3 GeV. The low-energy data are dominated by S11 wave which has two poles energy region below 2 Eleven nucleon resonances observed their decay into peta. At medium we find evidence a new resonance N(2070)D15 with (M,Gamma)=(2068+/-22, 295+/-40) MeV. gamma above 1.5 GeV, strong peak forward direction develops, signaling exchange of vector mesons t channel.
Total and differential cross sections for η η′photoproduction off the proton have been determined with CBELSA/TAPS detector photon energies between 0.85 2.55 GeV. The mesons are detected in their two neutral decay modes, η→γγ η→3π0→6γ, first time, cover full angular range cosθc.m. of meson. These new photoproduction data consistent earlier CB-ELSA results. η′ observed to π0π0η→6γ also extend coverage range.8 MoreReceived 8 September 2009DOI:https://doi.org/10.1103/PhysRevC.80.055202©2009...
Quasifree photoproduction of eta mesons off nucleons bound in the deuteron has been measured with CBELSA/TAPS detector for incident photon energies up to 2.5 GeV at Bonn ELSA accelerator. The have detected coincidence recoil protons and neutrons, which allows a detailed comparison quasifree n(gamma,eta)n p(gamma,eta)p reactions. excitation function production neutron shows pronounced bumplike structure W=1.68 (E{gamma} approximately 1 GeV), is absent proton.
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 exclusive photoproduction cross sections for Sigma(1385), Lambda(1405), and Lambda(1520) in reactions gamma + p -> K+ Y* using CLAS detector energies from near respective production thresholds up to a center-of-mass energy W of 2.85 GeV. The differential are integrated give total each hyperon. Comparisons made current theoretical models based on effective Lagrangian approach fitted previous data. accuracy these is seen vary widely. Lambda(1405) region strikingly different...
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...
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...
The first measurement is reported of the double-polarization observable G in photoproduction neutral pions off protons, covering photon energy range from 620 to 1120 MeV and full solid angle. describes correlation between polarization plane scattering for protons polarized along direction incoming photon. highly sensitive contributions baryon resonances. new results are compared predictions SAID, MAID, BnGa partial wave analyses. In spite long-lasting efforts understand γp→pπ0 as simplest...
Background: Measurements of polarization observables for the reactions $\stackrel{P\vec}{\ensuremath{\gamma}}p\ensuremath{\rightarrow}{K}^{+}\mathrm{\ensuremath{\Lambda}}$ and $\stackrel{P\vec}{\ensuremath{\gamma}}p\ensuremath{\rightarrow}{K}^{+}{\mathrm{\ensuremath{\Sigma}}}^{0}$ have been performed. This is part a program measurements designed to study spectrum baryon resonances in particular, nonperturbative QCD general.Purpose: The accurate measurement several provides tight constraints...
Single π0 photoproduction has been studied with the CB-ELSA experiment at Bonn using tagged photon energies between 0.3 and 3.0 GeV. The experimental setup covers a very large solid angle of ∼98% 4π. Differential cross sections dσ/dΩ have measured. Complicated structures in angular distributions indicate variety different resonances being produced s channel intermediate state γp→N∗(Δ∗)→pπ0. A combined analysis including data presented this letter along other sets reveals contributions from...
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...
This report presents a brief summary of the science opportunities and program polarized medium energy electron-ion collider at Jefferson Lab comprehensive description conceptual design such based on CEBAF electron accelerator facility.
Exclusive neutral-pion electroproduction ($ep\to e^\prime p^\prime \pi^0$) was measured at Jefferson Lab with a 5.75-GeV electron beam and the CLAS detector. Differential cross sections $d^4\sigma/dtdQ^2dx_Bd\phi_\pi$ structure functions $\sigma_T+\epsilon\sigma_L, \sigma_{TT}$ $\sigma_{LT}$ as of $t$ were obtained over wide range $Q^2$ $x_B$. The data are compared Regge handbag theoretical calculations. Analyses in both frameworks find that large dominance transverse processes is necessary...