Eur. Phys. J. C (2009) 64: 63-72
https://doi.org/10.1140/epjc/s10052-009-1126-8

Regular Article - Theoretical Physics

Quasi-particle model for lattice QCD: quark–gluon plasma in heavy ion collisions

¹ Department of Physics, Indian Institute of Technology Kanpur, Kanpur, 208 016, UP, India
² Raman Research Institute, C V Raman Avenue, Sadashivanagar, Bangalore, 560 080, India

^* e-mail: vinodc@iitk.ac.in

Received: 16 January 2009
Revised: 20 June 2009
Published online: 12 September 2009

Abstract

We propose a quasi-particle model to describe the lattice QCD equation of state for pure SU(3) gauge theory in its deconfined state, for T≥1.5T _c. The method involves mapping the interaction part of the equation of state to an effective fugacity of otherwise non-interacting quasi-gluons. We find that this mapping is exact. Using the quasi-gluon distribution function, we determine the energy density and the modified dispersion relation for the single particle energy, in which the trace anomaly is manifest. As an application, we first determine the Debye mass, and then the important transport parameters, viz., the shear viscosity, η, and the shear viscosity to entropy density ratio, . We find that both η and are sensitive to the interactions, and that the interactions significantly lower both η and .