Collective Oscillations of Majorana Neutrinos in Strong Magnetic Fields and Self-induced Flavor Equilibrium

International audienceWe study collective oscillations of Majorana neutrinos in some of the most extreme astrophysical sites such as neutron star merger remnants and magneto-rotational core-collapse supernovae which include dense neutrino media in the presence of strong magnetic fields. We show that neutrinos can reach flavor equilibrium if neutrino transition magnetic moment μν is strong enough, namely when μν/μB≳10-14–10-15 with μB being the Bohr magneton. This sort of flavor equilibrium, which is not necessarily flavor equipartition, can occur on (short) scales determined by the strength of the magnetic term in the Hamiltonian. Our findings can have interesting implications for the physics of such violent astrophysical environments