Langevin dynamics of heavy flavors in relativistic heavy-ion collisions

TL;DR

This paper models the stochastic motion of charm and bottom quarks in quark-gluon plasma using relativistic Langevin dynamics, comparing results with experimental data on heavy-ion collisions.

Contribution

It provides a detailed numerical approach to simulate heavy quark dynamics in relativistic heavy-ion collisions, including microscopic calculation of transport coefficients.

Findings

Reasonable agreement with experimental R_AA and v_2 data at high p_T.

Effective treatment of soft and hard collision contributions.

Integration of hydrodynamic background evolution with Langevin dynamics.

Abstract

We study the stochastic dynamics of c and b quarks, produced in hard initial processes, in the hot medium created after the collision of two relativistic heavy ions. This is done through the numerical solution of the relativistic Langevin equation. The latter requires the knowledge of the friction and diffusion coefficients, whose microscopic evaluation is performed treating separately the contribution of soft and hard collisions. The evolution of the background medium is described by ideal/viscous hydrodynamics. Below the critical temperature the heavy quarks are converted into hadrons, whose semileptonic decays provide single-electron spectra to be compared with the current experimental data measured at RHIC. We focus on the nuclear modification factor R_AA and on the elliptic-flow coefficient v_2, getting, for sufficiently large p_T, a reasonable agreement.