Third moments of conserved charges in QCD phase diagram

TL;DR

This paper discusses how third moments of conserved charges in QCD change signs near the phase boundary, offering a new way to probe the QCD phase diagram through experiments and lattice simulations.

Contribution

It introduces the concept that third moments of conserved charges can serve as indicators of the QCD phase boundary and can be measured experimentally and analyzed via lattice QCD.

Findings

Third moments change sign around the QCD phase boundary.

Sign changes can be measured in relativistic heavy ion collisions.

Lattice QCD can analyze these moments at small quark chemical potential.

Abstract

We point out that the third moments of conserved charges, the baryon and electric charge numbers, and energy, as well as their mixed moments, change their signs around the QCD phase boundary in the temperature and baryon chemical potential plane. These signs can be measured in relativistic heavy ion collisions, and will give clear information on the phase structure of QCD and the state of the system in the early stage of relativistic heavy ion collisions. The behaviors of these moments on the temperature axis and at small quark chemical potential can be analyzed in lattice QCD simulations. We emphasize that the third moments obtained on the lattice, together with the experimental results, will provide a deep understanding about the QCD phase diagram and the location of the state created in heavy ion collisions.