Photon radiation in hot nuclear matter by means of chiral anomalies

Abstract: A new mechanism of photon emission in the quark-gluon plasma is proposed. Photon dispersion relation in the presence of the $CP$-odd topological regions generated by the chiral anomaly acquires an imaginary mass. It allows photon radiation through the decay $q\to q\gamma$ and annihilation $q\bar q\to \gamma$ processes closely related to the chiral Cherenkov radiation. Unlike previous proposals this mechanism does not require an external magnetic field. The differential photon emission rate per unit volume is computed and shown to be comparable to the rate of photon emission in conventional processes.