57 research outputs found
Investigation of jet quenching and elliptic flow within a pQCD-based partonic transport model
The partonic transport model BAMPS (a Boltzmann approach to multiparton
scatterings) is employed to investigate different aspects of heavy ion
collisions within a common framework based on perturbative QCD. This report
focuses on the joint investigation of the collective behavior of the created
medium and the energy loss of high-pT gluons traversing this medium. To this
end the elliptic flow and the nuclear modification factor of gluons in heavy
ion collisions at 200 AGeV are simulated with BAMPS. The mechanism for the
energy loss of high energy gluons within BAMPS is studied in detail. For this,
purely elastic interactions are compared to radiative processes, gg -> ggg,
that are implemented based on the matrix element by Gunion and Bertsch. The
latter are found to be the dominant source of energy loss within the framework
employed in this work.Comment: To appear in the proceedings of the 26th Winter Workshop on Nuclear
Dynamics (2010)
Jet quenching and elliptic flow at RHIC and LHC within a pQCD-based partonic transport model
Fully dynamic simulations of heavy ion collisions at RHIC and at LHC energies
within the perturbative QCD-based partonic transport model BAMPS (Boltzmann
Approach to Multi-Parton Scatterings) are presented, focusing on the
simultaneous investigation of jet quenching and elliptic flow. The model
features inelastic 2 3 processes based on the Gunion-Bertsch matrix element
and has recently been extended to include light quark degrees of freedom,
allowing for direct comparison to hadronic data on the nuclear modification
factor via a fragmentation scheme for high-pT partons. The nuclear modification
factor of neutral pions in central Au+Au collisions at RHIC energy is compared
to experimental data. Furthermore first results on the nuclear modification
factor and the integrated elliptic flow of charged hadrons in Pb+Pb collisions
at LHC are presented and compared to recent ALICE data. These investigations
are complemented by a study on the suppression of D-mesons at LHC based on
elastic interactions with the medium.Comment: To appear in the proceedings of Quark Matter 201
Production, elliptic flow and energy loss of heavy quarks in the quark-gluon plasma
Production, elliptic flow and the nuclear modification factor of charm and
bottom quarks are studied in central and non-central heavy-ion collisions at
RHIC and LHC using the partonic transport model Boltzmann Approach of
MultiParton Scatterings (BAMPS). Employing an initial heavy quark yield
obtained with PYTHIA the full space-time evolution of charm and bottom quarks
in the quark-gluon plasma (QGP) is carried out with BAMPS, taking also
secondary production in the QGP into account. Only elastic collisions of heavy
quarks with particles from the medium cannot describe the experimentally
observed elliptic flow and nuclear modification factor. However, using an
improved Debye screening and the running coupling yields a result which is much
closer to data.Comment: 4 pages, 1 figure, to appear in the conference proceedings of Hot
Quarks 2010, few minor modifications in 2nd versio
Viscous Effects on Elliptic Flow and Shock Waves
Fast thermalization and a strong buildup of elliptic flow of QCD matter as
found at RHIC are understood as the consequence of perturbative QCD (pQCD)
interactions within the 3+1 dimensional parton cascade BAMPS. The main
contributions stem from pQCD bremsstrahlung processes.
By comparing to Au+Au data of the flow parameter as a function of
participation number the shear viscosity to entropy ratio is dynamically
extracted, which lies in the range of 0.08 and 0.2, depending on the chosen
coupling constant and freeze out condition. Furthermore, first simulations on
the temporal propagation of dissipative shock waves are given. The cascade can
either simulate true ideal shocks as well as initially diluted, truely viscous
shocks, depending on the employed cross sections or mean free path,
respectively.Comment: 7 pages, 8 figures, to appear in the proceedings of the 2008 Erice
School on Nuclear Physics, Sicil
Collective Flow and Energy Loss with parton transport
Quenching of gluonic jets and heavy quark production in Au+Au collisions at
RHIC can be understood within the pQCD based 3+1 dimensional parton transport
model BAMPS including pQCD bremsstrahlung processes.
Furthermore, the development of conical structures induced by gluonic jets is
investigated in a static box for the regimes of small and large dissipation.Comment: typos corrected, figure labels enlarged; Talk given by C. Greiner; to
appear in the proceedings of WISH201
Collective Flow and Mach Cones with Parton Transport
Fast thermalization and a strong build up of elliptic flow of QCD matter were
investigated within the pQCD based 3+1 dimensional parton transport model BAMPS
including bremsstrahlung processes. Within the same
framework quenching of gluonic jets in Au+Au collisions at RHIC can be
understood. The development of conical structure by gluonic jets is
investigated in a static box for the regimes of small and large dissipation.
Furthermore we demonstrate two different approaches to extract the shear
viscosity coefficient from a microscopical picture.Comment: 7 pages, 8 figures, 1 table; to appear in the proceedings of Hot and
Cold Baryonic Matter -- HCBM 201
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