Speaker
Prof.
Kyrill Bugaev
(Bogolyubov Institute for Theoretical Physics, Kiev, Ukraine)
Description
I would like to present several remarkable irregularities at chemical
freeze-out which are found using an advanced version of the hadron
resonance gas model. The most prominent of them are the sharp peaks of the
trace anomaly and baryonic charge density existing at chemical freeze-out
at the center-of-mass energies 4.9 GeV and 9.2 GeV. They are accompanied
by two sets of highly correlated quasi-plateaus in the collision energy
dependence of the entropy per baryon, total pion number per baryon, and
thermal pion number per baryon which are found at the center-of-mass
energies 3.8–4.9 GeV and 7.6–9.2 GeV. The low-energy set of quasi-plateaus
was predicted a long time ago. On the basis of the generalized
shock-adiabat model I show that the low-energy correlated quasi-plateaus
give evidence for the anomalous thermodynamic properties inside the mixed
phase found at the center-of-mass energies 4.3–4.9 GeV. In addition I
would like to discuss the thermostatic properties of the mixed phase and
the ones of an exponential mass spectrum of hadrons and to present the
practical conclusions for the chemical equilibration of strangeness in
heavy ion collisions. Using the similarity of low- and high-energy
irregularities I argue that the high-energy correlated quasi-plateaus may
correspond to a second phase transition. Its possible origin and a
possible location of the tricritical endpoint of QCD matter phase diagram
are also discussed.
Primary author
Prof.
Kyrill Bugaev
(Bogolyubov Institute for Theoretical Physics, Kiev, Ukraine)