26,610 research outputs found
Energy dependent kinetic freeze-out temperature and transverse flow velocity in high energy collisions
Transverse momentum spectra of negative and positive pions produced at
mid-(pseudo)rapidity in inelastic or non-single-diffractive proton-proton
collisions and in central nucleus-nucleus collisions over an energy range from
a few GeV to above 10 TeV are analyzed by a (two-component) blast-wave model
with Boltzmann-Gibbs statistics and with Tsallis statistics respectively. The
model results are in similarly well agreement with the experimental data
measured by a few productive collaborations who work at the Heavy Ion
Synchrotron (SIS), Super Proton Synchrotron (SPS), Relativistic Heavy Ion
Collider (RHIC), and Large Hadron Collider (LHC), respectively. The energy
dependent kinetic freeze-out temperature and transverse flow velocity are
obtained and analyzed. Both the quantities have quick increase from the SIS to
SPS, and slight increase or approximate invariability from the top RHIC to LHC.
Around the energy bridge from the SPS to RHIC, the considered quantities in
proton-proton collisions obtained by the blast-wave model with Boltzmann-Gibbs
statistics show more complex energy dependent behavior comparing with the
results in other three cases.Comment: 16 pages, 4 figures. The European Physical Journal A, accepted. arXiv
admin note: text overlap with arXiv:1805.0334
Transport model study of nuclear stopping in heavy ion collisions over an energy range from 0.09A GeV to 160A GeV
Nuclear stopping in the heavy ion collisions over a beam energy range from
SIS, AGS up to SPS is studied in the framework of the modified UrQMD transport
model, in which mean field potentials of both formed and "pre-formed" hadrons
(from string fragmentation) and medium modified nucleon-nucleon elastic cross
sections are considered. It is found that the nuclear stopping is influenced by
both the stiffness of the equation of state and the medium modifications of
nucleon-nucleon cross sections at SIS energies. At the high SPS energies, the
two-bump structure is shown in the experimental rapidity distribution of free
protons, which can be understood with the consideration of the "pre-formed"
hadron potentials.Comment: 15 pages, 7 figure
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