Anomaly induced cooling of Neutron Stars: A Standard Model contribution

Young neutron stars cool via the emission of neutrinos from their core. A precise understanding of all the different processes producing neutrinos in the hot and degenerate matter is essential for assessing the cooling rate of such stars. The main Standard Model processes contributing to this effect are $\nu$ bremsstrahlung, mURCA among others. In this paper, we investigate another Standard Model process initiated by the Wess-Zumino-Witten term, leading to the emission of neutrino pairs via $N\gamma \to N\nu \bar{\nu }$. We find that for proto-neutron stars, such processes, with degenerate neutrons, can be comparable and even dominate over the prototypical and well-known cooling mechanisms.