Thermal QCD deconfining phase transition in a finite volume within color-singletness and excluded volume effects: a finite size scaling analysis using cumulants

We study the properties of the deconfining phase transition for a finite-volume system in which the hadronic and quark–gluon plasma phases coexist and the finite extensions of the hadrons are taken into account. Finite-size effects are examined by probing the behavior of some useful response functions near the transition, and scaling exponents are determined using a finite-size scaling (FSS) analysis. For the shift scaling exponent, the finite-size transition point is determined from several definitions, and we propose new ways of defining this quantity, using cumulants of the probability distribution. Our study shows that the deconfining phase transition stays first-order, the scaling exponents being equal to unity. This result is consistent with the predictions of the standard FSS theoretical approaches to a first-order phase transition, and with results using Monte Carlo methods in lattice QCD and other models in statistical physics.