Abstract
We evaluate drag and diffusion transport coefficients comparing a quasi-particle approximation with on-shell constituents of the QGP medium and a dynamical quasi-particles model with off-shell bulk medium at finite temperature T. We study the effects of the width gamma of the particles of the bulk medium on the charm quark transport properties exploring the range where gamma < M_{q,g}. We find that off-shell effects are in general quite moderate and can induce a reduction of the drag coefficient at low momenta that disappear already at moderate momenta, p gtrsim 2–3 GeV. We also observe a moderate reduction of the breaking of the fluctuation–dissipation theorem (FDT) at finite momenta. Moreover, we have performed a first study of the dynamical evolution of HQ elastic energy loss in a bulk medium at fixed temperature extending the Boltzmann (BM) collision integral to include off-shell dynamics. A comparison among the Langevin dynamics, the BM collisional integral with on-shell and the BM extension to off-shell dynamics shows that the evolution of charm energy when off-shell effects are included remain quite similar to the case of the on-shell BM collision integral.
Highlights
Heavy quarks (HQs), namely charm and bottom, are considered as a solid probe to characterize the matter created in the QGP phase [1,2,3,4,5,6,7,8]
We evaluate drag and diffusion transport coefficients comparing a quasi-particle approximation with onshell constituents of the QGP medium and a dynamical quasiparticles model with off-shell bulk medium at finite temperature T
To investigate the differences between the heavy quark dynamics implied by Boltzmann on-shell dynamics and offshell dynamics, we study the heavy quark time evolution of t = 1 fm/c dN/dp [GeV ]
Summary
Heavy quarks (HQs), namely charm and bottom, are considered as a solid probe to characterize the matter created in the QGP phase [1,2,3,4,5,6,7,8]. The large mass of heavy quarks has several implications in this context. They are produced in the early stage of the collisions by pQCD process and being M H Q T the thermal pair production and annihilation processes are negligible. The HQ propagation through the QGP medium can be described as a diffusion a e-mail: process assimilated to a Brownian motion due to their large masses and perturbatice interaction leading to collisions with small momentum transfer [2,3,9]. The large mass has the effect to reduce the equilibration rate of heavy quarks in the medium relative to their light counterparts leading to a thermalization time comparable to the one of the life time of the fireball [3,10]. The standard approach to describe the propagation of HQ in QGP has been quite often treated within the framework of the Fokker–
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call