Nonstandard neutrino self-interactions can cause neutrino flavor equipartition inside the supernova core

Abstract

We show that non-standard neutrino self-interactions can lead to total flavor equipartition in a dense neutrino gas, such as those expected in core-collapse supernovae. In this first investigation of this phenomenon in the multi-angle scenario, we demonstrate that such a flavor equipartition can occur on very short scales, and therefore very deep inside the newly formed proto-neutron star, with a possible significant impact on the physics of core-collapse supernovae. Our findings imply that future galactic core-collapse supernovae can appreciably probe non-standard neutrino self-interactions, for certain cases even when they are many orders of magnitude smaller than the Standard Model terms.