Quasi-particle model for deconfined matter.pdf

a r X i v : h e p - p h / 0 2 1 2 1 7 9 v 1 1 2 D e c 2 0 0 2 February 1, 2008 20:0 WSPC/Trim Size: 9in x 6in for Proceedings garda QUASI-PARTICLE MODEL FOR DECONFINED MATTER? B. KA?MPFER Forschungszentrum Rossendorf, PF 510119, 01314 Dresden, Germany A. PESHIER Institut fu?r Theoretische Physik, Universita?t Giessen, 35392 Giessen, Germany G. SOFF Institut fu?r Theoretische Physik, TU Dresden, 01062 Dresden, Germany Our quasi-particle model for deconfined matter near Tc is reviewed. The extrap- olation of lattice QCD data to a finite baryo-chemical potential is discussed. De- termined by the chiral transition temperature Tc, the resulting equation of state of neutral and β-stable deconfined matter is soft and limits size and mass of pure quark stars. 1. Introduction Numerical Monte Carlo evaluations of QCD have succeeded to deliver the equation of state (EoS) of strongly interacting matter (quarks and gluons) with increasing accuracy. Near and slightly above the chiral transition temperature (which seems to coincide with the deconfinement temperature) Tc, the EoS shows a non-trivial behavior. It is, therefore, a challenge to develop models based on QCD, and catching its relevant degrees of freedom, which describe the EoS in a quantitative and transparent manner. A big deal of progress has been made by starting from first principles and arriving, after a chain of systematic approximations, at models which describe the lattice QCD data. Despite of several attempts, the range of applicability is restricted to temperatures T 2.5Tc. 1,2,3 Here, we are interested in the range Tc ? 3Tc which covers the physically important range for heavy- ion physics. We are going to review our phenomenological quasi-particle model and to describe its use for mapping lattice QCD data to a finite ?Work supported by BMBF and GSI. 1 February 1, 2008 20:0 WSPC/Trim Size: 9in x 6in for Proceedings garda 2 baryo-chemical potential. In contrast to the models derived directly from QCD,1,2,