2 research outputs found
Equation of state in the PNJL model with the entanglement interaction
The equation of state and the phase diagram in two-flavor QCD are
investigated by the Polyakov-loop extended Nambu--Jona-Lasinio (PNJL) model
with an entanglement vertex between the chiral condensate and the
Polyakov-loop. The entanglement-PNJL (EPNJL) model reproduces LQCD data at zero
and finite chemical potential better than the PNJL model. Hadronic degrees of
freedom are taken into account by the free-hadron-gas (FHG) model with the
volume-exclusion effect due to the hadron generation. The EPNJL+FHG model
improves agreement of the EPNJL model with LQCD data particularly at small
temperature. The quarkyonic phase survives, even if the correlation between the
chiral condensate and the Polyakov loop is strong and hadron degrees of freedom
are taken into account. However, the location of the quarkyonic phase is
sensitive to the strength of the volume exclusion.Comment: 9 pages, 7 figure
Chiral condensate and chemical freeze-out
We consider a chemical freeze-out mechanism which is based on a strong medium
dependence of the rates for inelastic flavor-equilibrating collisions based on
the delocalization of hadronic wave functions and growing hadronic radii when
approaching the chiral restoration. We investigate the role of mesonic (pion)
and baryonic (nucleon) fluctuations for melting the chiral condensate in the
phase diagram in the (T,mu)-plane. We apply the PNJL model beyond mean-field
and present an effective generalization of the chiral perturbation theory
result which accounts for the medium dependence of the pion decay constant
while preserving the GMOR relation. We demonstrate within a schematic resonance
gas model consisting of a variable number of pionic and nucleonic degrees of
freedom that within the above model a quantitative explanation of the hadonic
freeze-out curve and its phenomenological conditions can be given.Comment: 13 pages, 3 figure