A5077314115- High-Energy Particle Collisions Research
- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Particle Detector Development and Performance
- Nuclear physics research studies
- Radiation Detection and Scintillator Technologies
- Nuclear Physics and Applications
- Atomic and Molecular Physics
- CCD and CMOS Imaging Sensors
- Atomic and Subatomic Physics Research
- Nuclear reactor physics and engineering
- Astronomical and nuclear sciences
- X-ray Spectroscopy and Fluorescence Analysis
- Dark Matter and Cosmic Phenomena
- Medical Imaging Techniques and Applications
- Particle Accelerators and Free-Electron Lasers
- Electron and X-Ray Spectroscopy Techniques
- Advanced Data Storage Technologies
- Particle accelerators and beam dynamics
- Advanced Chemical Physics Studies
- Advanced X-ray and CT Imaging
- Neutrino Physics Research
- Pulsars and Gravitational Waves Research
- Cold Atom Physics and Bose-Einstein Condensates
- Magnetic confinement fusion research
GSI Helmholtz Centre for Heavy Ion Research
2016-2025
Max Planck Institute for Nuclear Physics
1998-2025
Goethe University Frankfurt
2015-2024
Goethe Institute
2010-2024
Instituto de Estructura de la Materia
2016-2022
University of Wuppertal
2022
Helmholtz-Zentrum Dresden-Rossendorf
2009-2021
Slovak Academy of Sciences
2018-2019
Institute of Physics of the Slovak Academy of Sciences
2018-2019
Lawrence Berkeley National Laboratory
2015
Fragment distributions resulting from $\mathrm{Au}+\mathrm{Au}$ collisions at an incident energy of $E/A\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}600\phantom{\rule{0ex}{0ex}}\mathrm{MeV}$ are studied. From the measured fragment and neutron mass excitation decaying prefragments were determined. A temperature scale was derived observed yield ratios He Li isotopes. The relation between this isotope system exhibits a behavior which is expected for phase transition. nuclear vapor regime...
This paper presents a comprehensive review of both the theory and experimental successes Quantum Chromodynamics, starting with its emergence as well defined in 1972-73 following developments results up to present day. Topics include earliest theoretical foundations; fundamental constants QCD; an introductory discussion lattice QCD, only known method for obtaining exact predictions from methods approximating special focus on effective field theories; QCD under extreme conditions; measurements...
The three-body breakup ${}^{6}{\stackrel{\ensuremath{\rightarrow}}{\mathrm{He}}}^{4}\mathrm{He}+n+n$ is studied experimentally, using a secondary ${}^{6}\mathrm{He}$ ion beam of 240 MeV/nucleon incident on carbon and lead targets. Integrated cross sections for one- two-neutron knockout differential $d\ensuremath{\sigma}{/dE}^{*}$ $d\ensuremath{\sigma}/d\ensuremath{\vartheta}$ inelastic nuclear or electromagnetic excitations into the continuum are presented. $E$1-strength distribution deduced...
We present phase space distributions and multiplicities of K+, K−, ϕ mesons produced in Ar+KCl reactions at a kinetic beam energy 1.756 GeV/nucleon measured with the HADES spectrometer. The inverse slope parameters yields kaons supplement systematics previous measurements. percentage K− coming from decay is found to be 18±7%.6 MoreReceived 9 March 2009DOI:https://doi.org/10.1103/PhysRevC.80.025209©2009 American Physical Society
We present transverse momentum spectra, rapidity distribution and multiplicity of $ \Lambda$ -hyperons measured with the HADES spectrometer in reaction Ar(1.76AGeV) + KCl . The yield \Xi^{{-}}_{}$ is calculated from our previously reported /( \Sigma^{{0}}_{}$ ) ratio compared to other strange particle multiplicities. Employing a strangeness balance equation multiplicities yet unmeasured \Sigma^{{\pm}}_{}$ can be estimated. Finally statistical hadronization model used fit yields \pi^{-}_{}$ ,...
We report first results on a deep subthreshold production of the doubly strange hyperon Xi;{-} in heavy-ion reaction. At beam energy 1.76A GeV reaction Ar + KCl was studied with High Acceptance Di-Electron Spectrometer at SIS18/GSI. A high-statistics and high-purity Lambda sample collected, allowing for investigation decay channel --> Lambdapi;{-}. The deduced Xi;{-}/(Lambda Sigma;{0}) ratio (5.6 +/- 1.2_{-1.7};{+1.8}) x 10;{-3} is significantly larger than available model predictions.
We present a search for the e+e− decay of hypothetical dark photon, also named U vector boson, in inclusive dielectron spectra measured by HADES p(3.5 GeV) + p, Nb reactions, as well Ar (1.756 GeV/u) KCl reaction. An upper limit on kinetic mixing parameter squared ϵ2 at 90% CL has been obtained mass range MU=0.02–0.55 GeV/c2 and is compared with world data set. For masses 0.03–0.1 GeV/c2, lowered respect to previous results, allowing now exclude large part region favored muon g−2 anomaly....
Employing the Bonn–Gatchina partial wave analysis framework (PWA), we have analyzed HADES data of reaction p(3.5GeV)+p→pK+Λ. This might contain information about kaonic cluster "ppK−" (with quantum numbers JP=0− and total isospin I=1/2) via its decay into pΛ. Due to interference effects in our coherent description data, a hypothetical K‾NN (or, specifically "ppK−") signal need not necessarily show up as pronounced feature (e.g. peak) an invariant mass spectrum like Our PWA includes variety...
The dipole response of stable and unstable neutron-rich oxygen nuclei masses A = 17 to 22 has been investigated experimentally utilizing electromagnetic excitation in heavy-ion collisions at beam energies about 600 MeV/nucleon. kinematically complete measurement the neutron decay channel inelastic scattering secondary projectiles from a Pb target was performed. Differential cross sections d sigma/dE were derived up 30 MeV energy. In contrast nuclei, deduced strength distribution appears be...
Peripheral fragmentation of a 287 MeV/nucleon beam the halo nucleus ${}^{11}\mathrm{Li}$ incident on carbon target has been studied in fragment-neutron coincidence experiment. The momentum distribution ${}^{10}\mathrm{Li}$ fragments gives access to removed neutron ${}^{11}\mathrm{Li}$. From shape distribution, $({1s}_{1/2}{)}^{2}$ contribution mixture and $({0p}_{1/2}{)}^{2}$ components ground-state wave function was determined be $(45\ifmmode\pm\else\textpm\fi{}10)%$. angular correlation...
Multifragmentation has been measured for $^{197}\mathrm{Au}$${+}^{197}$Au collisions at E/A=100, 250, and 400 MeV. The mean fragment multiplicity increases monotonically with the charged particle E/A=100 MeV, but decreases central incident energy, consistent onset of nuclear vaporization. Molecular dynamics calculations follow some trends underpredict observed multiplicities. Including statistical decay excited residues improves agreement peripheral worsens it collisions.
We present the transverse momentum spectra and rapidity distributions of ${\ensuremath{\pi}}^{\ensuremath{-}}$ ${\mathrm{K}}_{S}^{0}$ in Ar $+$ KCl reactions at a beam kinetic energy $1.756$ $A$ GeV measured with High Acceptance Di-Electron Spectrometer (HADES). The reconstructed sample is characterized by good event statistics for wide range rapidity. compare experimental to predictions Isospin Quantum Molecular Dynamics (IQMD) model. model calculations show that low momenta constitute...
We report measurements of electron pair production in elementary p+p and d+p reactions at 1.25 GeV/u with the HADES spectrometer. For first time, pairs were reconstructed for n+p by detecting proton spectator from deuteron breakup. find that yield invariant mass Me+e- > 0.15 GeV/c2 is about an order magnitude larger as compared to p+p. A comparison model calculations demonstrates mechanism not sufficiently described yet. The spectra measured C+C are compatible a superposition collisions,...
We present results on dielectron production in ${}^{40}\mathrm{Ar}+\mathrm{KCl}$ collisions at 1.76$A$ GeV. For the first time $\ensuremath{\omega}$ mesons could be reconstructed a heavy-ion reaction bombarding energy which is well below threshold free nucleon-nucleon collisions. The multiplicity has been extracted and compared to yields of other particles, particular $\ensuremath{\varphi}$ meson. At intermediate ${e}^{+}{e}^{\ensuremath{-}}$ invariant masses, we find strong enhancement pair...
We present an analysis of the Lambda(1405) resonance produced in reaction p+p->Sigma^{pm}+pi^{mp}+K+p at 3.5 GeV kinetic beam energy measured with HADES GSI. The two charged decay channels -> Sigma^{\pm}+pi^{\mp} have been reconstructed for first time p+p collisions. efficiency and acceptance-corrected spectral shapes show a peak position clearly below 1400 MeV/c^2. find total production cross section sigma_{Lambda(1405)}=9.2 +- 0.9 0.7 +3.3-1.0 mub. its polar angle distribution suggests...
The global polarization of {\Lambda} hyperons along the total orbital angular momentum a relativistic heavy-ion collision is presented based on high statistics data samples collected in Au+Au collisions at \sqrt{s_{NN}} = 2.4 GeV and Ag+Ag 2.55 with High-Acceptance Di-Electron Spectrometer (HADES) GSI, Darmstadt. This first measurement below strangeness production threshold nucleon-nucleon collisions. Results are reported as function centrality well hyperon transverse (p_T) rapidity (y_{CM})...
Reactions of the halo systems 11Be and 11Li (at 460 280 MeV/nucleon) with a carbon target demonstrate that ( n+9Li) has an (unbound) l=0 ground state very close to threshold. The neutron appreciable (1s1/2)2 (0p1/2)2 components.Received 20 December 1994DOI:https://doi.org/10.1103/PhysRevLett.75.1719©1995 American Physical Society
The nuclear response of a medium-mass nucleus ${(}^{136}$Xe) to electromagnetic excitation in near-relativistic heavy-ion collision was investigated the ${\mathrm{reaction}}^{136}$Xe(0.7A GeV)+Pb. From an exclusive measurement neutron decay excited $^{136}\mathrm{Xe}$ projectiles, strong excitations giant resonances and, particular, double isovector dipole resonance were identified. A energy 28.3\ifmmode\pm\else\textpm\fi{}0.7 MeV, width 6.3\ifmmode\pm\else\textpm\fi{}1.6 and total cross...
We present data on collective flow of neutrons in collisons 197Au + at 400 MeV/nucleon. The azimuthal distribution about the beam axis is investigated with respect to reaction plane as determined from light charged particles. ''squeezeout'' neutrons, perpendicular plane, observed for first time. Quantitative agreement a high level accuracy found between behavior and hydrogen ions.Received 29 April 1993DOI:https://doi.org/10.1103/PhysRevLett.71.963©1993 American Physical Society
We present the inclusive invariant-mass, transverse momentum and rapidity distributions of dielectrons (e$^{+}$e$^{-}$ pairs) in p+p interactions at 3.5 GeV beam kinetic energy. In vector-meson mass region, a distinct peak corresponding to direct $\omega$ decays is reconstructed with 2% resolution. The data compared predictions from three model calculations. Due large acceptance HADES apparatus for $e^{+}e^{-}$ invariant masses above 0.2 GeV/$c^{2}$ pair momenta p$_{t}$ $ <$ 1 GeV/$c$,...