4,069 research outputs found
Rapidity-dependence of jet shape broadening and quenching
The jet shape modification due to partonic energy loss in the dense QCD
matter is investigated by the help of the special transverse energy-energy
correlator in the vicinity of maximum energy deposition of every event. In the
accepted scenario with scattering of jet hard partons off comoving medium
constituents this correlator is independent of the pseudorapidity position of a
jet axis and becomes considerably broader (symmetrically over the
pseudorapidity and the azimuthal angle) in comparison with -collisions. At
scattering off "slow" medium constituents the broadening of correlation
functions is dependent on the pseudorapidity position of a jet axis and
increases noticeably in comparison with the previous scenario for jets with
large enough pseudorapidities. These two considered scenarios result also in
the different dependence of jet quenching on the pseudorapidity.Comment: 9 pages, 7 figures, 1 table, RevTex4, typos corrected, accepted for
publication in Phys. Rev.
Dynamical vs geometric anisotropy in relativistic heavy-ion collisions: which one prevails?
We study the influence of geometric and dynamical anisotropies on the
development of flow harmonics and, simultaneously, on the second- and
third-order oscillations of femtoscopy radii. The analysis is done within the
Monte Carlo event generator HYDJET++, which was extended to dynamical
triangular deformations. It is shown that the merely geometric anisotropy
provides the results which anticorrelate with the experimental observations of
either (or ) or second-order (or third-order) oscillations of the
femtoscopy radii. Decays of resonances significantly increase the emitting
areas but do not change the phases of the radii oscillations. In contrast to
the spatial deformations, the dynamical anisotropy alone provides the correct
qualitative description of the flow and the femtoscopy observables
simultaneously. However, one needs both types of the anisotropy to match
quantitatively the experimental data.Comment: minor corrections, published versio
Anisotropic flow fluctuations in hydro-inspired freeze-out model for relativistic heavy ion collisions
The LHC data on event-by-event harmonic flow coefficients measured in PbPb
collisions at center-of-mass energy 2.76 TeV per nucleon pair are analyzed and
interpreted within the HYDJET++ model. To compare the model results with the
experimental data the unfolding procedure is employed. The essentially
dynamical origin of the flow fluctuations in hydro-inspired freeze-out approach
has been established. It is shown that the simple modification of the model via
introducing the distribution over spatial anisotropy parameters permits
HYDJET++ to reproduce both elliptic and triangular flow fluctuations and
related to it eccentricity fluctuations of the initial state at the LHC energy.Comment: 12 pages including 9 figures as EPS-files; prepared using LaTeX
package for publication in the European Physical Journal
HYDRO + JETS (HYDJET++) event generator for Pb+Pb collisions at LHC
The Monte Carlo event generator HYDJET++ is one of the few generators,
designed for the calculations of heavy-ion collisions at ultrarelativistic
energies, which combine treatment of soft hydro-like processes with the
description of jets traversing the hot and dense partonic medium. The model is
employed to study the azimuthal anisotropy phenomena, dihadron angular
correlations and event-by-event (EbyE) fluctuations of the anisotropic flow in
Pb+Pb collisions at TeV. The interplay of soft and hard
processes describes the violation of the mass hierarchy of meson and baryon
elliptic and triangular flows at p_T > 2 GeV/c, the fall-off of the flow
harmonics at intermediate transverse momenta, and the worsening of the
number-of-constituent-quark (NCQ) scaling of elliptic/triangular flow at LHC
compared to RHIC energies. The cross-talk of v_2 and v_3 leads to emergence of
higher order harmonics in the model and to appearance of the ridge structure in
dihadron angular correlations in a broad pseudorapidity range. HYDJET++
possesses also the dynamical EbyE fluctuations of the anisotropic flow. The
model results agree well with the experimental data.Comment: 8 pages, 6 figures, contribution to Proceedings of the Winter
Workshop on Nuclear Dynamics 201
Modeling the jet quenching, thermal resonance production and hydrodynamical flow in relativistic heavy ion collisions
The event topology in relativistic heavy ion collisions is determined by
various multi-particle production mechanisms. The simultaneous model treatment
of different collective nuclear effects at high energies (such as a hard
multi-parton fragmentation in hot QCD-matter, thermal resonance production,
hydrodynamical flows, etc.) is actual but rather complicated task. We discuss
the simulation of the above effects by means of Monte-Carlo model HYDJET++.Comment: Talk given at Workshop "Hot Quarks 2010" (La Londe Les Maures,
France, June 21-26, 2010); 4 pages including 2 figures as EPS-files; prepared
using LaTeX package for publication in Journal of Physics: Conference Serie
Higher harmonics of azimuthal anisotropy in relativistic heavy ion collisions in HYDJET++ model
The LHC data on azimuthal anisotropy harmonics from PbPb collisions at
center-of-mass energy 2.76 TeV per nucleon pair are analyzed and interpreted in
the framework of the HYDJET++ model. The cross-talk of elliptic and
triangular flow in the model generates both even and odd harmonics of
higher order. Comparison with the experimental data shows that this mechanism
is able to reproduce the and centrality dependencies of
quadrangular flow , and also the basic trends for pentagonal and
hexagonal flows.Comment: 12 pages including 13 figures as EPS-files; prepared using LaTeX
package for publication in the European Physical Journal
- …