5,608 research outputs found
Critical behaviors near the (tri-)critical end point of QCD within the NJL model
We investigate the dynamical chiral symmetry breaking and its restoration at
finite density and temperature within the two-flavor Nambu-Jona-Lasinio model,
and mainly focus on the critical behaviors near the critical end point (CEP)
and tricritical point (TCP) of quantum chromodynamics. The multi-solution
region of the Nambu and Wigner ones is determined in the phase diagram for the
massive and massless current quark, respectively. We use the various
susceptibilities to locate the CEP/TCP and then extract the critical exponents
near them. Our calculations reveal that the various susceptibilities share the
same critical behaviors for the physical current quark mass, while they show
different features in the chiral limit
Locate QCD Critical End Point in a Continuum Model Study
With a modified chemical potential dependent effective model for the gluon
propagator, we try to locate the critical end point (CEP) of strongly
interacting matter in the framework of Dyson-Schwinger equations (DSE). Beyond
the chiral limit, we find that Nambu solution and Wigner solution could coexist
in some area. Using the CornwallJackiw-Tomboulis (CJT) effective action, we
show that these two phases are connected by a first order phase transition. We
then locate CEP as the end point of the first order phase transition line.
Meanwhile, based on CJT effective action, we give a direct calculation for the
chiral susceptibility and thereby study the crossover.Comment: 9 pages, 7 figures; Version published in JHE
The Wigner Solution and QCD Phase Transitions in a Modified PNJL Model
By employing some modification to the widely used two-flavor Polyakov-loop
extended Nambu-Jona-Lasinio (PNJL) model, we discuss the Wigner solution of the
quark gap equation at finite temperature and zero quark chemical potential
beyond the chiral limit, and then try to explore its influences on the chiral
and deconfinement phase transitions of QCD at finite temperature and zero
chemical potential. The discovery of the coexistence of the Nambu and the
Wigner solutions of the quark gap equation with nonzero current quark mass at
zero temperature and zero chemical potential, as well as their evolutions with
temperature is very interesting for the studies of the phase transitions of
QCD. According to our results, the chiral phase transition might be of first
order (while the deconfinement phase transition is still a crossover, as in the
normal PNJL model), and the corresponding phase transition temperature is lower
than that of the deconfinement phase transition, instead of coinciding with
each other, which are not the same as the conclusions obtained from the normal
PNJL model. In addition, we also discuss the sensibility of our final results
on the choice of model parameters
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