Neutrino Masses in a Neutrinosphere

Abstract: The energies of neutrinos in a neutrinosphere, the dense matter created after the gravitational collapse of a massive star, are estimated. Cubic equations for energy eigenvalues of neutrinos are used, with the effective masses found by taking the neutrinos at rest in neutrinosphere matter. Large differences in the effective mass of some neutrino species in a neutrinosphere compared to vacuum are found.