Speaker
Description
The behavior of the U(1) axial anomaly under extreme conditions is an important issue for understanding the QCD phase structure and the properties of hadrons. In particular, the topological susceptibility characterizes the strength of U(1) axial symmetry breaking, and its relation to chiral symmetry restoration in hot and dense matter has been extensively discussed.
Based on the Ward–Takahashi identities, the topological susceptibility can be expressed in terms of meson susceptibilities. Using this expression, we analyze its behavior at finite temperature and density within simple chiral effective models. We show that the topological susceptibility decreases with the restoration of chiral symmetry. Based on this result, we discuss the relation between chiral symmetry restoration and U(1) axial symmetry restoration within the framework of the effective model.