Fluctuation-induced modifications of the phase structure in (2+1)-flavor QCD

TL;DR

This study uses a non-perturbative functional renormalization group approach to analyze how fluctuations affect the phase structure of (2+1)-flavor QCD at finite temperature and chemical potential, revealing significant quantitative impacts.

Contribution

It introduces a detailed non-perturbative analysis of fluctuation effects on the chiral phase transition in (2+1)-flavor QCD, highlighting the sensitivity of meson properties to these fluctuations.

Findings

Fluctuations significantly alter the phase transition characteristics.

The pseudoscalar meson complex's flavor composition is highly sensitive to fluctuations.

Implications for the assignment of chiral partners in QCD phenomenology.

Abstract

The low-energy sector of QCD with $N_f = 2\!+\!1$ dynamical quark flavors at non-vanishing chemical potential and temperature is studied with a non-perturbative functional renormalization group method. The analysis is performed in different truncations in order to explore fluctuation-induced modifications of the quark-meson correlations as well as quark and meson propagators on the chiral phase transition of QCD. Depending on the chosen truncation significant quantitative implications on the phase transition are found. In the chirally symmetric phase, the quark flavor composition of the pseudoscalar $(\eta,\eta^{\prime})$-meson complex turns out to be drastically sensitive to fluctuation-induced modifications in the presence of the axial $U(1)_A$ anomaly. This has important phenomenological consequences for the assignment of chiral partners to these mesons.