Toward a simultaneous description of $R_{AA}$ and $v_2$ for heavy quarks

TL;DR

This paper investigates how combining four key ingredients in heavy quark models can better simultaneously describe the nuclear suppression factor and elliptic flow observed in heavy-ion collisions, highlighting the importance of interaction dynamics.

Contribution

The study introduces a comprehensive approach incorporating temperature-dependent energy loss, Boltzmann collision solutions, hadronization by coalescence, and hadronic rescattering to improve modeling of heavy quark observables.

Findings

Different models with the same R_AA can produce varying v_2 values.

Interaction dynamics significantly influence the elliptic flow predictions.

A consistent combination of ingredients helps address the R_AA and v_2 puzzle.

Abstract

The two key observables related to heavy quarks that have been measured in RHIC and LHC energies are the nuclear suppression factor $R_{AA}$ and the elliptic flow $v_2$. Simultaneous description of these two observables is a top challenge for all the existing models. We have highlighted how a consistent combination of four ingredients i.e the temperature dependence of the energy loss, full solution of the Boltzmann collision integral for the momentum evolution of heavy quark, hadronization by coalescence, then the hadronic rescattering, responsible to address a large part of such a puzzle. We have considered four different models to evaluate the temperature dependence of drag coefficients of the heavy quark in QGP. All these four different models are set to reproduce the same $R_{AA}$ as of the experiments. We have shown that for the same $R_{AA}$, the $v_2$ could be quite different depending on the interaction dynamics as well as other ingredients.