Scaling properties of net-baryon number fluctuations at the deconfinement critical point

TL;DR

This paper studies the critical behavior of net-baryon number fluctuations near the deconfinement critical point in QCD, connecting fluctuations to Polyakov loop susceptibilities and analyzing their scaling properties.

Contribution

It derives critical exponents using Landau theory, validates them with numerical models, and estimates the critical region size considering beyond-mean-field effects.

Findings

Critical exponents are derived and validated for net-baryon fluctuations.

The critical region shrinks with increasing baryon density.

Scaling functions from the 3D Ising model are used to estimate beyond-mean-field exponents.

Abstract

We investigate the critical behavior of the first four cumulants of the net-baryon number near the deconfinement critical point in QCD in the limit of heavy quarks. By connecting baryon-number fluctuations to Polyakov loop susceptibilities, we analyze their mean-field scaling properties at zero and non-zero baryon chemical potentials. In the mean-field approximation we derive critical exponents via the Landau theory and validate them through explicit numerical calculations in an effective Polyakov loop model. Using a Ginzburg-Landau criterion as a diagnostic of beyond-mean-field effects, we estimate the size of the critical region and find that it shrinks with increasing baryon density. By utilizing the exact scaling function in the 3D Ising model, we estimate critical exponents beyond the mean-field approximation.