B. Zihlmann
A5042977604- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Atomic and Subatomic Physics Research
- Nuclear physics research studies
- Nuclear Physics and Applications
- Advanced NMR Techniques and Applications
- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Superconducting Materials and Applications
- Radiation Detection and Scintillator Technologies
- Particle Accelerators and Free-Electron Lasers
- Magnetic confinement fusion research
- Atomic and Molecular Physics
- Quantum, superfluid, helium dynamics
- X-ray Spectroscopy and Fluorescence Analysis
- Particle accelerators and beam dynamics
- Advanced Chemical Physics Studies
- Medical Imaging Techniques and Applications
- Electron and X-Ray Spectroscopy Techniques
- Photocathodes and Microchannel Plates
- Cold Fusion and Nuclear Reactions
- Nuclear reactor physics and engineering
- Radiation Therapy and Dosimetry
- Quantum chaos and dynamical systems
Mississippi State University
2024
Thomas Jefferson National Accelerator Facility
2011-2023
Ruhr University Bochum
2023
National and Kapodistrian University of Athens
2023
University of Virginia
2001-2022
Northwestern University
2021
Duke University
2021
William & Mary
2021
Williams (United States)
2021
Hamburg Institut (Germany)
2010-2020
Measurements are reported of the proton and deuteron spin structure functions ${g}_{1}^{p}$ ${g}_{1}^{d}$ at beam energies 29.1, 16.2, 9.7 GeV, ${g}_{2}^{p}$ ${g}_{2}^{d}$ a energy 29.1 GeV. The integrals ${\ensuremath{\Gamma}}_{p}={\ensuremath{\int}}_{0}^{1}{g}_{1}^{p}{(x,Q}^{2})dx$ ${\ensuremath{\Gamma}}_{d}={\ensuremath{\int}}_{0}^{1}{g}_{1}^{d}{(x,Q}^{2})dx$ were evaluated fixed ${Q}^{2}=3(\mathrm{GeV}{/c)}^{2}$ using full data set to yield...
We have measured the ratio $\frac{{g}_{1}^{p}}{{F}_{1}^{p}}$ over range $0.029<x<0.8$ and $1.3<{Q}^{2}<10$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$ using deep-inelastic scattering of polarized electrons from ammonia. An evaluation integral $\ensuremath{\int}{0}^{1}{g}_{1}^{p}(x, {Q}^{2})\mathrm{dx}$ at fixed ${Q}^{2}=3$ yields 0.127\ifmmode\pm\else\textpm\fi{}0.004(stat)\ifmmode\pm\else\textpm\fi{}0.010(syst), in agreement with previous experiments, but well below Ellis-Jaffe sum...
Separated longitudinal and transverse structure functions for the reaction 1H(e,e(')pi(+))n were measured in momentum transfer region Q2 = 0.6--1.6 (GeV/c)(2) at a value of invariant mass W 1.95 GeV. New values pion charge form factor extracted from cross section by using recently developed Regge model. The results indicate that this is larger than previously assumed consistent with monopole parametrization fitted to very low elastic data.
The charged pion form factor, ${F}_{\ensuremath{\pi}}({Q}^{2})$, is an important quantity that can be used to advance our knowledge of hadronic structure. However, the extraction ${F}_{\ensuremath{\pi}}$ from data requires a model ${}^{1}\mathrm{H}(e,{e}^{'}{\ensuremath{\pi}}^{+})n$ reaction and thus inherently dependent. Therefore, detailed description factor electroproduction obtained recently at Jefferson Lab presented, with particular focus given dominant uncertainties in this procedure....
We report on a high-statistics measurement of the deuteron spin structure function ${g}_{1}^{d}$ at beam energy 29 GeV in kinematic range $0.029<x<0.8$ and $1<{Q}^{2}<10$ (GeV $/c$${)}^{2}$. The integral ${\ensuremath{\gamma}}_{1}^{d}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ensuremath{\int}{1}^{}{g}_{1}^{d}\mathrm{dx}$ evaluated fixed ${Q}^{2}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}3$ $/c$${)}^{2}$ gives...
We report on precision measurements of the elastic cross section for electron-proton scattering performed in Hall C at Jefferson Lab. The were made 28 distinct kinematic settings covering a range momentum transfer $0.4<{Q}^{2}<5.5\phantom{\rule{0.3em}{0ex}}{(\mathrm{GeV}∕c)}^{2}$. These represent significant contribution to world's data set ${Q}^{2}$ range, where large discrepancy currently exists between ratio electric magnetic proton form factors extracted from previous and that recently...
The data analysis for the reaction H(e,e' pi^+)n, which was used to determine values charged pion form factor Fpi of Q^2=0.6-1.6 GeV^2, has been repeated with careful inspection all steps and special attention systematic uncertainties. Also method extract from measured longitudinal cross section critically reconsidered. Final separated transverse sections extracted are presented.
Precise data on the neutron magnetic form factor G_{mn} have been obtained with measurements of ratio cross sections D(e,e'n) and D(e,e'p) up to momentum transfers Q^2 = 0.9 (GeV/c)^2. Data typical uncertainties 1.5% are presented. These allow for first time extract a precise value radius neutron.
New measurements are reported on the deuteron spin structure function g_1^d. These results were obtained from deep inelastic scattering of 48.3 GeV electrons polarized deuterons in kinematic range 0.01 < x 0.9 and 1 Q^2 40 (GeV/c)^2. first high dose electron data using lithium deuteride (6Li2H) as target material. Extrapolations performed to obtain moments g_1^d, including Gamma_1^d, net quark polarization Delta Sigma.
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 have measured the spin structure functions g2p and g2d virtual photon asymmetries A2p A2d over kinematic range 0.02⩽x⩽0.8 0.7⩽Q2⩽20GeV2 by scattering 29.1 32.3 GeV longitudinally polarized electrons from transversely NH3 6LiD targets. Our g2 approximately follows twist-2 Wandzura–Wilczek calculation. The twist-3 reduced matrix elements d2p d2n are less than two standard deviations zero. data inconsistent with Burkhardt–Cottingham sum rule if there is no pathological behavior as x→0....
We have measured proton and deuteron virtual photon-nucleon asymmetries ${A}_{2}^{p}$ ${A}_{2}^{d}$ structure functions ${g}_{2}^{p}$ ${g}_{2}^{d}$ over the range $0.03<x<0.8$ $1.3<{Q}^{2}<10(\mathrm{GeV}/c{)}^{2}$ by inelastically scattering polarized electrons off ammonia targets. Results for ${A}_{2}$ are significantly smaller than positivity limit $\sqrt{R}$ both Within experimental precision ${g}_{2}$ data well described twist-2 contribution, ${g}_{2}^{\mathrm{WW}}$. Twist-3 matrix...
Cross sections for the reaction ${}^{1}\mathrm{H}(e,{e}^{'}{\ensuremath{\pi}}^{+})n$ were measured in Hall C at Thomas Jefferson National Accelerator Facility (JLab) using high-intensity Continuous Electron Beam (CEBAF) to determine charged pion form factor. Data taken central four-momentum transfers ranging from ${Q}^{2}=0.60$ 2.45 ${\mathrm{GeV}}^{2}$ an invariant mass of virtual photon-nucleon system $W=1.95$ and 2.22 GeV. The cross separated into four structure functions...
We have carried out an (e,e′p) experiment at high momentum transfer and in parallel kinematics to measure the strength of nuclear spectral function S(k,E) nucleon momenta k large removal energies E. This is related presence short-range tensor correlations, was known hitherto only indirectly with considerable uncertainty from lack independent-particle region. locates by direct measurement correlated predicted theory.Received 18 May 2004DOI:https://doi.org/10.1103/PhysRevLett.93.182501©2004...
A bstract comprehensive set of azimuthal single-spin and double-spin asymmetries in semi-inclusive leptoproduction pions, charged kaons, protons, antiprotons from transversely polarized protons is presented. These include the previously published HERMES results on Collins Sivers asymmetries, analysis which has been extended to also an extraction a three-dimensional kinematic binning enlarged phase space. They are complemented by corresponding for remaining four allowed one-photon-exchange...
We have measured the spin structure functions g2p and g2d virtual photon asymmetries A2p A2d over kinematic range 0.02≤x≤0.8 1.0≤Q2≤30 (GeV/c)2 by scattering 38.8 GeV longitudinally polarized electrons from transversely NH3 6LiD targets. The absolute value of A2 is significantly smaller than R positivity limit range, while g2 consistent with twist-2 Wandzura-Wilczek calculation. obtain results for twist-3 reduced matrix elements d2p, d2d d2n. Burkhardt-Cottingham sum rule integral ∫g2(x)dx...
The ratio g1F1 has been measured over the range 0.03 < x 0.6 and 0.3 Q2 10 (GeV/c)2 using deep-inelastic scattering of polarized electrons from protons deuterons. We find to be consistent with no Q2-dependence at fixed in region > 1 (GeV/c)2. A trend is observed for decrease lower Q2. Fits world data without a possible are agreement Bjorken sum rule, but Δq substantially less than quark-parton model expectation.
Inclusive electron scattering is measured with 4.045 GeV incident beam energy from C, Fe, and Au targets. The transfers angles correspond to a kinematic range for Bjorken $x>1$ momentum ${Q}^{2}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1--7(\mathrm{GeV}/c{)}^{2}$. When analyzed in terms of the $y$-scaling function data show first time an approach scaling values initial nucleon momenta significantly greater than nuclear matter Fermi (i.e., $>0.3\mathrm{GeV}/c$).
We report the results from a systematic study of quasielastic $(e,{e}^{\ensuremath{'}}p)$ reaction on $^{12}\mathrm{C},\phantom{\rule{0.5em}{0ex}}^{56}\mathrm{Fe}$, and $^{197}\mathrm{Au}$ performed at Jefferson Lab. have measured nuclear transparency extracted spectral functions (corrected for radiation) over ${Q}^{2}$ range $0.64--3.25\phantom{\rule{0.5em}{0ex}}{(\text{GeV}∕c)}^{2}$ all three nuclei. In addition, we separated longitudinal transverse 0.64...
The ( ${e,e}^{\ensuremath{'}}p$) reaction was studied on targets of C, Fe, and Au at momentum transfers squared ${Q}^{2}$ 0.6, 1.3, 1.8, $3.3{\mathrm{GeV}}^{2}$ in a region kinematics dominated by quasifree electron-proton scattering. Missing energy missing distributions are reasonably well described plane wave impulse approximation calculations with $A$ dependent corrections that measure the attenuation final state protons.
The quasielastic ${(e,e}^{\ensuremath{'}}p)$ reaction was studied on targets of deuterium, carbon, and iron up to a value momentum transfer ${Q}^{2}$ $8.1(\mathrm{GeV}{/c)}^{2}.$ A nuclear transparency determined by comparing the data calculations in plane-wave impulse approximation. dependence mass number investigated search for onset color phenomenon. We find no evidence within our range ${Q}^{2}.$ fit world's reflects energy free-proton--nucleon cross section.
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...