Self-consistent quasiparticle model for quark-gluon plasma.pdf

a r X i v : h e p - p h / 0 6 0 9 1 8 8 v 1 1 9 S e p 2 0 0 6 Self-consistent quasiparticle model for quark-gluon plasma Vishnu M. Bannur Department of Physics, University of Calicut, Kerala-673 635, India. February 2, 2008 Abstract Here we present a self-consistent quasi-particle model for quark-gluon plasma and apply it to explain the non-ideal behaviour seen in lattice simulations. The basic idea, borrowed from electrodynamic plasma, is that the gluons acquire mass as it propagates through plasma due to collective effects and is approximately equal to the plasma frequency. The statistical mechanics and thermodynamics of such a system is studied by treating it as an ideal gas of massive gluons. Since mass or plasma frequency depends on density, which itself is a thermodynamic quantity, the whole problem need to be solved self-consistently. PACS Nos : 12.38.Mh, 12.38.Gc, 05.70.Ce, 52.25.Kn Keywords : Equation of state, quark-gluon plasma, quasiparticle quark-gluon plasma. 1 1 Introduction : The quasiparticle model of quark-gluon plasma (qQGP) is used to study the thermal properties of quark- gluon plasma (QGP) [1, 2, 3, 4, 5]. QGP is a plasma of quarks and gluons which exhibits a collective behaviour because of the interactions, governed by quantum chromodynamics (QCD). At extreamly high temperature, the interaction may be very weak because of the asymptotic freedom and hence the plasma is almost ideal gas of quarks and gluons. However, near and above the critical Tc, the coupling constant αs is not weak and hence QGP may be non-ideal gas of quarks and gluons. Here Tc is the critical temperature of phase transition or cross over from hadrons to QGP. The lattice simulation of QCD at finite temperature [6] (LGT) and the elliptical flow observed in relativistic heavy ion collisions (RHICs) signal the existance of non- ideal QGP. The problem of confinement-deconfinement of QCD and the search for QGP in RHICs depend on the properties of QGP at temperature close to