Non-perturbative effects for the Quark-Gluon Plasma equation of state
- PDF / 614,744 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 19 Downloads / 178 Views
ELEMENTARY PARTICLES AND FIELDS Theory
Non-Perturbative Effects for the Quark–Gluon Plasma Equation of State* V. V. Begun1), 2)** , M. I. Gorenstein1), 2)*** , and O. A. Mogilevsky1) Received March 31, 2011
Abstract—The non-perturbative effects for the Quark–Gluon Plasma (QGP) equation of state (EoS) are considered. The modifications of the bag model EoS are constructed to satisfy the main qualitative features observed for the QGP EoS in the lattice QCD calculations. A quantitative comparison with the lattice results is done for the SU (3) gluon plasma and for the QGP with dynamical quarks. Our analysis advocates a negative value of the bag constant B. DOI: 10.1134/S1063778812060038
1. INTRODUCTION A transition to the deconfined phase of quarks and gluons, the quark–gluon plasma (QGP), is expected at high temperature and/or baryonic density (see, e.g., [1] and [2] and references therein). In the present study of the QGP equation of state (EoS) we consider the system with zero values of all conserved charges. This is approximately valid for the QGP created in nucleus–nucleus collisions at the BNL RHIC and even better for experiments at the CERN LHC. Up to now the strongly interacting matter EoS could be only calculated from the first principles within the lattice QCD. These calculations are done for zero or very small values of the baryonic chemical potential. The QGP exists at high temperatures T > Tc , where the critical temperature Tc corresponds to the 1storder phase transition in the pure SU (3) gluodynamics or to a smooth crossover in the full QCD. The main results for the QCD deconfined matter EoS can be illustrated by the Monte-Carlo (MC) lattice results (LR) for the energy density ε(T ) and pressure p(T ) in the SU (3) gluodynamics [3]. The qualitative features of the EoS at T > Tc can be summarized as follows. The pressure p(T ) is very small at the critical temperature, p(Tc )/Tc4 1, and rapidly increases at T Tc . At high T the system reaches the ideal massless gas behavior p ∼ = ε/3, thus, ε(T ) ∼ = σT 4 . However, the constant σ which regulates the hightemperature behavior is about 10% smaller than the Stefan–Boltzmann (SB) constant σSB . The recent ∗
The text was submitted by the authors in English. Bogolyubov Institute for Theoretical Physics, Kiev, Ukraine. 2) Frankfurt Institute for Advanced Studies, Germany. ** E-mail: [email protected] *** E-mail: [email protected] 1)
lattice estimate for the pressure at very high temperatures T /Tc ∼ = 107 is still about 3% below the SB limit [4]. Both ε/T 4 and 3p/T 4 approach the value σ from below. The interaction measure (ε − 3p)/T 4 , called also the trace anomaly, demonstrates a prominent maximum at T ∼ = 1.1Tc . Note that these properties of the gluon plasma EoS are also valid in the full QCD [5–7]. The bag model (BM) [8] was invented to describe the mass spectrum of the hadron states. Soon after that it was suggested [9] to interpret the bag constant B as the non-perturbative energy density term in the deconfined matter EoS. For several decades, th
Data Loading...
