Speaker
Elena Bratkovskaya
(FIAS)
Description
Authors: T. Song, H. Berrehrah, D. Cabrera, J.M. Torres-Rincon, L. Tolos, W. Cassing and E. Bratkovskaya
The charm production in ultra-relativistic heavy-ion
collisions is studied based on the Parton-Hadron-String Dynamics (PHSD)
transport approach. The initial charm quarks are produced by the
Pythia event generator tuned to fit the transverse momentum
spectrum and rapidity distribution of charm quarks from
Fixed-Order Next-to-Leading Logarithm (FONLL) calculations.
The shadowing effect is accounted for the nuclei collisions.
The produced charm quarks scatter in the quark-gluon plasma (QGP)
with the off-shell partons whose masses and widths are given by
the Dynamical Quasi-Particle Model (DQPM), which reproduces the
lattice QCD equation-of-state in thermal equilibrium. The relevant
cross sections are calculated in a consistent way by employing the
effective propagators and couplings from the DQPM. Close to the
critical energy density of the phase transition, the charm quarks
are hadronized into $D$ mesons through coalescence and
fragmentation. The hadronized $D$ mesons then interact with the
various hadrons in the hadronic phase with cross sections
calculated in an effective lagrangian approach with heavy-quark
spin symmetry. The nuclear modification factor
$R_{AA}$ and the elliptic flow $v_2$ of $D^0$ mesons from PHSD are
compared with the experimental data from the STAR Collaboration
for Au+Au collisions at $\sqrt{s_{NN}}$ =200 GeV
and to the ALICE data for Pb+Pb collisions at $\sqrt{s_{NN}}$ =2.76 TeV.
We find that in the PHSD the energy loss of $D$ mesons at high $p_T$ can be
dominantly attributed to partonic scattering while the actual
shape of $R_{AA}$ versus $p_T$ reflects the heavy-quark
hadronization scenario, i.e. coalescence versus fragmentation.
Also the hadronic rescattering is important for the $R_{AA}$
at low $p_T$ and enhances the $D$-meson elliptic flow $v_2$.
Reference: arXiv:1503.03039 [nucl-th]
| On behalf of collaboration: | NONE |
|---|
Author
Elena Bratkovskaya
(FIAS)
