Emergent chiral spin symmetry, non-perturbative dynamics and thermoparticles in hot QCD

TL;DR

This paper explores non-perturbative phenomena in hot QCD, revealing an intermediate chiral spin symmetry region with hadron-like excitations and introducing the concept of thermoparticles as key thermal constituents.

Contribution

It demonstrates the existence of an intermediate chiral spin symmetry region and introduces thermoparticles as non-perturbative thermal excitations in hot QCD.

Findings

Identification of an intermediate chiral spin symmetry region in hot QCD.

Evidence for thermoparticles as non-perturbative thermal constituents.

Lattice data supporting the existence of hadron-like excitations at high temperatures.

Abstract

Several non-perturbative results for hot QCD are challenging some aspects of the phase diagram and its associated degrees of freedom which were previously believed to be well understood. With increasing temperature, the chiral crossover is followed by an intermediate region with an approximate chiral spin symmetry larger than chiral symmetry, in which pseudo-scalar mesons continue to exist as hadron-like excitations, before at some higher temperature the expected chiral symmetry is recovered. By testing general formal considerations against lattice data, it can be shown that thermally modified versions of stable vacuum particles, so-called thermoparticles, form the constituents of thermal quantum field theories, with properties quite different from what is expected perturbatively. This ``viewpoint'' aims to raise broader and, in particular, phenomenological interest in these directions.