$U_A(1)$ symmetry restoration in QCD with $N_f$ flavors
  Recently, there have been reports that the chirally restored phase of QCD is effectively symmetric under $U(N_f) \times U(N_f)$ rather than $SU(N_f)\times SU(N_f)$. We supplement their argument by including the contributions from topologically nontrivial gauge field configurations and discuss how the conclusions are modified. General statements are made concerning the particle spectrum of QCD with light $N_f$ flavors in the high temperature chirally restored phase. 
Su H. Lee and T. Hatsuda