# Medium Modification of Charm Production in Relativistic Heavy Ion Collisions due to Pre-equilibrium Dynamics of Partons at $\sqrt{s_{\textrm {NN}}}$= 0.2--5.02 TeV

## TL;DR

This paper investigates how pre-equilibrium parton dynamics affect charm quark production in relativistic heavy ion collisions at RHIC and LHC energies, revealing significant suppression compared to proton-proton collisions.

## Contribution

It introduces a parton cascade model to study charm production dynamics during the pre-equilibrium phase of heavy ion collisions, highlighting the suppression effects.

## Key findings

- Significant suppression of charm quark production in AA collisions compared to pp collisions.
- Pre-equilibrium dynamics play a crucial role in charm quark yield modifications.
- Results are relevant for understanding charm quark energy loss in quark-gluon plasma.

## Abstract

We study the production dynamics of charm quarks in the parton cascade model for relativistic heavy ion collisions at RHIC and LHC energies. The model is eminently suited for a study of the pre-equilibrium dynamics of charm quarks at modest transverse momenta. The treatment is motivated by QCD parton picture and describes the dynamics of an ultra-relativistic heavy-ion collision in terms of cascading partons which undergo scattering and multiplication while propagating. We find considerable suppression of charm quarks production in $AA$ collisions compared to those for $pp$ collisions at the same $\sqrt{s_{\text {NN}}}$ scaled by number of collisions. This may be important for an accurate determination of energy loss suffered by charm quarks while traversing the thermalized quark gluon plasma.