The critical exponents of the QCD (tri)critical endpoint within exactly solvable models

TL;DR

This paper calculates critical exponents of the Quark Gluon Bags with Surface Tension Model at its tricritical and critical endpoints, analyzing their universality and scaling relations.

Contribution

It introduces two new parameters for the model and examines their impact on critical exponents and universality classes, including non-Fisher classes.

Findings

Critical exponents are derived as functions of model parameters.

Some scaling relations are not fulfilled for the standard alpha' index.

A modified index alpha'_s restores scaling relations, suggesting alternative universality classes.

Abstract

The critical indices alpha', beta, gamma' and delta of the Quark Gluon Bags with Surface Tension Model with the tricritical and critical endpoint are calculated as functions of the usual parameters of this model and two newly introduced parameters (indices). The critical indices are compared with that ones of other models. The universality class of the present model with respect to values of the model parameters is discussed. The scaling relations for the found critical exponents are verified and it is demonstrated that for the standard definition of the index alpha' some of them are not fulfilled in general case. Although it is shown that the specially defined index alpha'_s recovers the scaling relations, another possibility, an existence of the non-Fisher universality classes, is also discussed.