Abstract:
We estimate axion mass in a QCD medium. To take into consideration the non-perturbative nature of the QCD we model the QCD medium using three (2+1) flavor Polyakov loop extended Nambu Jona Lasinio (PNJL) model. Axion is incorporated within the framework of the PNJL model through the Kobayashi-Maskawa-t'hooft determinant interaction. We argue that chiral transition and confinement-deconfinement transition affect the mass of axion in a QCD medium. Our results suggest that the in-medium mass of axion is correlated with the chiral and confinement-deconfinement transition. We compare our results with the Nambu Jona Lasinio (NJL) model results and Lattice QCD calculations.