Selected challenges in low-energy QCD and hadron physics

TL;DR

This paper discusses key unresolved issues in low-energy QCD, including chiral symmetry breaking, the relationship between chiral and deconfinement transitions, and the QCD phase diagram at low temperature and density.

Contribution

It provides a summary of current debates and challenges in understanding fundamental aspects of low-energy QCD based on panel discussions.

Findings

Uncertainty about the status of chiral symmetry breaking.

Debates on the entanglement of chiral and deconfinement transitions.

Limited knowledge of the QCD phase diagram at low temperature and baryon density.

Abstract

This presentation briefly addresses three basic issues of low-energy QCD: first, whether the Nambu-Goldstone scenario of spontaneous chiral symmetry breaking is well established; secondly, whether there is a dynamical entanglement of the chiral and deconfinement crossover transitions in QCD; and thirdly, what is the status of knowledge about the phase diagram of QCD at low temperature and non-zero baryon density. These three topics were injected as key words into a panel discussion at the Schladming school on Challenges in QCD. The following exposition reflects the style and character of the discussions, with no claim of completeness.