On the relevance of matter and glue dynamics for baryon number fluctuations

TL;DR

This paper explores how matter and glue dynamics influence baryon number fluctuations and kurtosis near the QCD chiral crossover, revealing nuanced effects of confinement and effective distributions.

Contribution

It introduces a comprehensive framework incorporating momentum-dependent scattering, dispersions, and backreaction effects to study baryon fluctuations in low energy QCD.

Findings

Baryon number fluctuations change rapidly near the chiral crossover.

Kurtosis of baryon distribution shows significant variation with temperature.

Effective distributions in confining backgrounds differ from traditional colorless baryonic expectations.

Abstract

We investigate the impact of the matter and glue dynamics on baryon number fluctuations and the kurtosis of baryon number distribution. This is done within the framework of QCD-improved low energy effective models. In particular we include the momentum scale dependence of the quark-meson scattering and the non-trivial dispersions of both, quarks and mesons. On the gluonic side we take into account the backreaction of the matter sector on the glue dynamics. It is shown that the above fluctuations lead to a more rapid change of the baryon number fluctuations as well as the kurtosis of with the chiral crossover. We also study the signatures of quark confinement in low energy QCD. It is shown that contrary to the common picture the effective thermal distribution in the presence of confining glue backgrounds does not tend towards the colourless baryonic one. Instead, the dominance of colourless hadronic states is obtained in a subtle interplay of quark and glue contributions to the canonical potential.