Patterns and partners within the QCD phase diagram including strangeness

TL;DR

This paper reviews the patterns of chiral symmetry restoration in QCD, focusing on partner degeneration, Ward Identities, and the role of strangeness, comparing effective theories with lattice data around the transition region.

Contribution

It analyzes chiral symmetry restoration patterns and the role of strangeness using Ward Identities and effective theories, providing insights compatible with lattice data.

Findings

Partner degeneration patterns for $O(4)$ and $U(1)_A$ symmetries analyzed.

Effective theories like Chiral Perturbation Theory align with lattice data.

Strangeness plays a significant role in the chiral transition context.

Abstract

We review the current situation of the pattern of chiral symmetry restoration. In particular, we analyze partner degeneration for $O(4)$ and $U(1)_A$ symmetries within the context of Ward Identities and Effective Theories. The application of Ward Identities to the thermal scaling of screening masses is also discussed. We present relevant observables for which an Effective Theory description in terms of Chiral Perturbation Theory and its unitarized extension are compatible with lattice data even around the transition region. We pay special attention to the role of strangeness in this context.