Eur. Phys. J. C (2015) 75: 80
https://doi.org/10.1140/epjc/s10052-015-3297-9

Letter

Charm contribution to bulk viscosity

Institute for Theoretical Physics, Albert Einstein Center, University of Bern, Sidlerstrasse 5, 3012, Bern, Switzerland

^* e-mail: laine@itp.unibe.ch

Received: 30 December 2014
Accepted: 28 January 2015
Published online: 18 February 2015

Abstract

In the range of temperatures reached in future heavy ion collision experiments, hadronic pair annihilations and creations of charm quarks may take place within the lifetime of the plasma. As a result, charm quarks may increase the bulk viscosity affecting the early stages of hydrodynamic expansion. Assuming thermalisation, we estimate the charm contribution to bulk viscosity within the same effective kinetic theory framework in which the light parton contribution has been computed previously. The time scale at which this physics becomes relevant is related to the width of the transport peak associated with the trace anomaly correlator and is found to be  fm/c for  MeV.