Supernovae, Neutrino Rest Mass, and the Middle‐Energy Neutrino Background in the Universe

Abstract

Neutrinos emitted during the formation of the neutron stars and black holes form, together with relict microwave radiation and relict neutrinos, a background for the present universe. The energy of the kind of neutrino emitted in neutron star formation, at 3-30 MeV, is much greater than that of relict neutrinos and much smaller than that of the cosmic ray neutrinos. They are accordingly designated middle energy neutrinos (MENs). It is presently shown that the MEN background's density, at 2-10 x 10 to the -33rd gm/cu cm, is greater than the density of relict microwave radiation and less than the density of matter. The MEN spectra presently calculated yield 0.002 to 0.008 solar neutrino units in the solar chlorine-argon detector. Possible neutrino rest mass effects are discussed for the cases of expanding universe propagation and MEN background spatial structure. 12 references.