T-dependence of the axion mass when the U_A(1) and chiral symmetry breaking are tied

Dubravko Klabučar, Davor Horvatić, Dalibor Kekez

Modulo the scale of spontaneous breaking of Peccei-Quinn symmetry, the axion mass $m_a(T)$ is given by the QCD topological susceptibility $\chi (T)$ at all temperatures $T$. From an ap…