G. W. Hoffmann
A5028733275- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Particle physics theoretical and experimental studies
- Nuclear physics research studies
- Nuclear Physics and Applications
- Additive Manufacturing and 3D Printing Technologies
- Mechanical Behavior of Composites
- Textile materials and evaluations
- Nuclear reactor physics and engineering
- Atomic and Molecular Physics
- Advanced NMR Techniques and Applications
- Particle Detector Development and Performance
- Advanced Chemical Physics Studies
- Breast Cancer Treatment Studies
- Structural Analysis and Optimization
- Astronomical and nuclear sciences
- Superconducting Materials and Applications
- Radiation Detection and Scintillator Technologies
- Atomic and Subatomic Physics Research
- Bioinformatics and Genomic Networks
- Statistical Methods in Clinical Trials
- X-ray Spectroscopy and Fluorescence Analysis
- Stochastic processes and statistical mechanics
- Gene expression and cancer classification
- Particle Accelerators and Free-Electron Lasers
TU Dresden
2014-2023
Johannes Gutenberg University Mainz
2014-2023
St. Josefs Hospital
2023
Institute of Textile Technology and Process Engineering
2013-2023
University Hospital and Clinics
2023
Marienhospital Stuttgart
2023
Marienhospital Bottrop
2023
The University of Texas at Austin
2010-2021
AGH University of Krakow
2014-2018
University of California, Los Angeles
1971-2017
Collisions between prolate uranium nuclei are used to study how particle production and azimuthal anisotropies depend on initial geometry in heavy-ion collisions. We report the two- four-particle cumulants, $v_2\{2\}$ $v_2\{4\}$, for charged hadrons from U+U collisions at $\sqrt{s_{\rm NN}}$ = 193 GeV Au+Au 200 GeV. Nearly fully overlapping selected based amount of energy deposited by spectators STAR Zero Degree Calorimeters (ZDCs). Within this sample, observed dependence multiplicity...
Azimuthal anisotropy (v(2)) and two-particle angular correlations of high p(T) charged hadrons have been measured in Au+Au collisions at sqrt[s(NN)]=130 GeV for transverse momenta up to 6 GeV/c, where hard processes are expected contribute significantly. The exhibit elliptic flow a structure suggestive fragmentation partons. monotonic rise v(2)(p(T)) p(T)<2 GeV/c is consistent with collective hydrodynamical calculations. At p(T)>3 saturation v(2) observed which persists p(T)=6 GeV/c.
We report the first measurement of strange (Lambda) and antistrange (Lambda macro) baryon production from square root [s(NN)]=130 GeV Au+Au collisions at Relativistic Heavy Ion Collider (RHIC). Rapidity density transverse mass distributions midrapidity are presented as a function centrality. The yield Lambda Lambda; hyperons is found to be approximately proportional number negative hadrons. relative hadrons increases very rapidly with momentum. magnitude increase cannot described by existing...
New 500-MeV ${p}_{\mathrm{pol}}$+$^{40,\phantom{\rule{0ex}{0ex}}48}\mathrm{Ca}$, $^{90}\mathrm{Zr}$, and $^{208}\mathrm{Pb}$ elastic $\frac{d\ensuremath{\sigma}}{d\ensuremath{\Omega}}$ ${A}_{y}(\ensuremath{\theta})$ data are presented. The small-momentum-transfer not reproduced by the second-order Kerman-McManus-Thaler optical potential which uses free nucleon-nucleon amplitudes. systematics of these results, taken together with previous 800-MeV suggest that medium modifications to...
The observation of $\ensuremath{\Lambda}$-hypernuclear levels in $_{\ensuremath{\Lambda}}^{12}\mathrm{C}$ by associated production through the (${\ensuremath{\pi}}^{+}, {K}^{+}$) reaction is reported. excitation-energy spectra were recorded at laboratory scattering angles 5.6\ifmmode^\circ\else\textdegree\fi{}, 10.3\ifmmode^\circ\else\textdegree\fi{}, and 15.2\ifmmode^\circ\else\textdegree\fi{}. They show two major peaks---one attributed to ground state, one about 11 MeV higher. These...
Analyses of 0.8 and 1 GeV $p$+$^{208}\mathrm{Pb}$ elastic angular distribution data have obtained neutron-proton root-mean-square radius differences ($\ensuremath{\Delta}{r}_{\mathrm{np}}$) which are not consistent. Therefore, the experiment was repeated using a high resolution spectrometer. The new higher precision consistent with older data, apart from 15% overall normalization difference. A second order Kerman-McManus-Thaler optical model analysis model-independent neutron density, yields...
The first order, spin-dependent microscopic proton-nucleus optical potential of Kerman, McManus, and Thaler is used to analyze 800 MeV polarized proton elastic differential cross section analyzing power data for target nuclei $^{58}\mathrm{Ni}$, $^{90}\mathrm{Zr}$, $^{116,124}\mathrm{Sn}$, $^{208}\mathrm{Pb}$. Approximately model-independent neutron density distributions are constructed in order investigate the uncertainty deduced densities resulting from statistical error finite range...
We present measurements of second-order azimuthal anisotropy $({v}_{2})$ at midrapidity $(|y|<1.0)$ for light nuclei $d,\phantom{\rule{0.16em}{0ex}}t,\phantom{\rule{0.16em}{0ex}}^{3}\mathrm{He}$ (for $\sqrt{{s}_{NN}}=200$, 62.4, 39, 27, 19.6, 11.5, and 7.7 GeV) antinuclei $\overline{d}$ ($\sqrt{{s}_{NN}}=200$, 19.6 $^{3}\overline{\mathrm{He}}$ ($\sqrt{{s}_{NN}}=200$ in the STAR (Solenoidal Tracker RHIC) experiment. The ${v}_{2}$ these produced heavy-ion collisions is compared with those $p$...
Elliptic flow (v_2) values for identified particles at midrapidity in Au + collisions measured by the STAR experiment Beam Energy Scan Relativistic Heavy Ion Collider sqrt{s_{NN}}= 7.7--62.4 GeV are presented three centrality classes. The dependence and data 14.5 new. Except lowest beam energies we observe a similar relative v_2 baryon-meson splitting all classes which is agreement within 15% with number-of-constituent quark scaling. larger most to antiparticles, already observed minimum...
The balance function is a new observable based on the principle that charge locally conserved when particles are pair produced. Balance functions have been measured for charged particle pairs and identified pion in Au+Au collisions at square root of SNN = 130 GeV Relativistic Heavy Ion Collider using STAR. peripheral widths consistent with model predictions superposition nucleon-nucleon scattering. Widths central smaller, trends predicted by models incorporating late hadronization.
The spin rotation parameter $Q$ has been measured for $p$-$^{40}\mathrm{Ca}$ elastic scattering at 497 MeV $0.01<~\ensuremath{-}t<~0.15$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$ with use of the new high-resolution spectrometer focalplane polarimeter. In conjunction analyzing power and differential cross section, this measurement uniquely determines amplitudes up to an arbitrary phase. A parameter-free analysis within Glauber diffractive approximation $N\ensuremath{-}N$ phase-shift...
Azimuthal correlations of charged hadrons with direct-photon ($γ_{dir}$) and neutral-pion ($π^{0}$) trigger particles are analyzed in central Au+Au minimum-bias $p+p$ collisions at $\sqrt{s_{_{NN}}} = 200$ GeV the STAR experiment. The charged-hadron per-trigger yields mid-rapidity from compared to quantify suppression collisions. away-side associated-particle per $γ_{dir}$ is independent transverse momentum particle ($p_{T}^{\mathrm{trig}}$), whereas smaller low associated...
We report the first measurement of inclusive antiproton production at midrapidity in Au+Au collisions square root s(NN) = 130 GeV by STAR experiment RHIC. The transverse mass distributions measured momentum range 0.25<p( perpendicular)<0.95 GeV/c are found to fall less steeply for more central collisions. extrapolated rapidity density is scale approximately with negative hadron multiplicity density.
We present the first measurement of midrapidity vector meson φ production in Au+Au collisions at RHIC (√sNN=130GeV) from STAR detector. For 11% highest multiplicity collisions, slope parameter an exponential fit to transverse mass distribution is T=379±50(stat)±45(syst)MeV, yield dN/dy=5.73±0.37(stat)±0.69(syst) per event, and ratio Nφ/Nh− found be 0.021±0.001(stat)±0.004(syst). The measured T for do not change selected bins.Received 17 August...
New and/or corrected 800 MeV $p+^{40,42,44,48}\mathrm{Ca}$ elastic angular distributions are presented. The data, together with analyzing power measurements, analyzed to investigate the isotopic neutron and matter density differences between these four calcium isotopes. analysis employs a local, spin-dependent form of second order Kerman, McManus, Thaler optical potential in which approximately model-independent forms for densities assumed. Nucleon-nucleon amplitude uncertainties occur at...
Differential cross sections for inelastic proton scattering at 800 MeV have been measured a number of low-lying states in $^{90}\mathrm{Zr}$, $^{120}\mathrm{Sn}$, $^{144}\mathrm{Sm}$, and $^{208}\mathrm{Pb}$. The data from this earlier experiments on $^{40}\mathrm{Ca}$ $^{58}\mathrm{Ni}$ were analyzed with collective vibrational model to obtain separate neutron deformation lengths, making use electromagnetic measurements. Ratios transition matrix elements are calculated. These ratios...
Results of relativistic and nonrelativistic impulse approximation calculations are compared for p+$^{40}\mathrm{Ca}$ elastic scattering observables between 181 1040 MeV. At 400 MeV above, the approach is superior, especially with regard to spin observables. Below MeV, neither calculation agrees well experiment.NUCLEAR REACTIONS Energy dependence approximation, Dirac phenomenology, invariant nucleon-nucleon amplitudes, nucleon-nucleus scattering, ${E}_{\mathrm{p}}=181\ensuremath{-}1040$
Differential cross sections and analyzing powers have been measured for elastic inelastic scattering of 800-MeV protons by $^{16}\mathrm{O}$. Microscopic analyses utilizing the impulse approximation are used to study ground-state neutron distribution $^{16}\mathrm{O}$, demonstrate importance spin-orbit amplitudes transitions.
The acceptance-corrected dielectron excess mass spectra, where the known hadronic sources have been subtracted from inclusive are reported for first time at mid-rapidity |yee|<1 in minimum-bias Au+Au collisions sNN=19.6 and 200 GeV. spectra consistently described by a model calculation with broadened ρ spectral function Mee<1.1GeV/c2. integrated yield sNN=19.6GeV 0.4<Mee<0.75GeV/c2, normalized to charged particle multiplicity mid-rapidity, has value similar that In+In sNN=17.3GeV. For...
The first measurements of light antinucleus production in Au+Au collisions at the Relativistic Heavy-Ion Collider are reported. observed rates for d macro and (3)He much larger than lower energy nucleus-nucleus collisions. A coalescence model analysis yields indicates that there is little or no increase antinucleon freeze-out volume compared to CERN SPS energy. These analyses also indicate smaller volume.