Neutral pion decay into $\nu \bar{\nu }$ in dense skyrmion matter

Abstract

We study the weak decay of the neutral pion to a neutrino-antineutrino pair, ${\pi }^0\to \nu \bar{\nu }$, in the Skyrme model. In baryon free-space the process is forbidden by helicity while in a dense baryonic medium, the process becomes possible already to leading order in $G_F$ due to the break-down of Lorentz symmetry in the background medium.

7 pages, RevTeX, 4 figures. Expanded discussion in light of referee comments