Cold+Hot Matter cosmology with m(νμ)[approximately-equal-to]m(ντ)[approximately-equal-to]2.4 eV

Abstract

Recent Kamiokande data supports the νμ→ντ neutrino oscillation explanation of the deficit of cosmic ray muon neutrinos, which requires that the muon and tau neutrinos have almost identical masses; and preliminary evidence from the current Los Alamos neutrino oscillation experiment suggests that the mass of the muon neutrino m(νμ) is ≳2.4 eV. Two neutrinos of mass 2.4 eV each would constitute ‘‘hot’’ dark matter accounting for a fraction Ων=0.2(0.5/h) 2 of critical density. Here we consider the consequences of such neutrino masses for cosmological models for the formation of galaxies and large scale structure in the universe, which are spatially flat and in which most of the dark matter is ‘‘cold.’’ The linear calculations and N‐body simulations that we report here indicate that an Ω=1 Cold+Hot Dark Matter (CHDM) cosmological model with two neutrinos each of mass ∼2.4 eV (we will call this model Cν2DM) agrees remarkably well with all available observations. However, we find that this is true only if the Hu...