Heavy quark transport at RHIC and LHC

TL;DR

This paper models heavy quark transport in heavy ion collisions at RHIC and LHC, predicting elliptic flow and nuclear modification factors using a Langevin approach within a hybrid model.

Contribution

It introduces a novel Langevin-based simulation of heavy quark dynamics incorporating resonance scattering and multiple hadronization mechanisms at different energies.

Findings

Reproduces experimental $v_2$ and $R_{AA}$ data at RHIC and LHC

Shows the impact of hadronization mechanisms on heavy flavor observables

Provides insights into heavy quark-medium interactions in quark-gluon plasma

Abstract

We calculate the heavy quark evolution in heavy ion collisions and show results for the elliptic flow $v_2$ as well as the nuclear modification factor $R_{AA}$ at RHIC and LHC energies. For the calculation we implement a Langevin approach for the transport of heavy quarks in the UrQMD (hydrodynamics + Boltzmann) hybrid model. As drag and diffusion coefficients we use a Resonance approach for elastic heavy-quark scattering and assume a decoupling temperature of the charm quarks from the hot medium of $130\,\text{MeV}$. At RHIC energies we use a coalescence approach at the decoupling temperature for the hadronization of the heavy quarks to D-mesons and B-mesons and a sub-following decay to heavy flavor electrons using PYTHIA. At LHC we use an additional fragmentation mechanism to account for the higher transverse momenta reached at higher collision energies.