1998/10/13 by Joel R. Primack, Michael Groß, Primack, Joel R. +2
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #astro-ph #hep-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9810204
8 pages, Latex+blois.sty+psfig.sty, including 2 inlined postscript figures. To be published in the proceedings of the Xth Rencontres de Blois, "The Birth of Galaxies", 28 June - 4 July 1998. A computational error has been corrected, leading to substantial corrections to the figures but relatively minor corrections to the implications
The recent atmospheric neutrino data from Super-Kamiokande provide strong evidence of neutrino oscillations and therefore of non-zero neutrino mass. These data imply a lower limit on the hot dark matter (i.e., light neutrino) contribution to the cosmological density Ων>~ 0.001 --- almost as much as that of all the stars in the universe --- and permit higher Ων. The ``standard'' COBE-normalized critical-matter-density (i.e., Ωm=1) Cold Dark Matter (CDM) model has too much power on small scales. But adding to CDM neutrinos with mass of about 5 eV, corresponding to Ων≈ 0.2, results in a much improved fit to data on the nearby galaxy and cluster distribution. Indeed, the resulting Cold + Hot Dark Matter (CHDM) cosmological model is arguably the most successful Ωm=1 model for structure formation. However, other recent data has begun to make the case for Ωm <~ 0.6 fairly convincing. In light of all this new data, we reconsider whether cosmology still provides evidence favoring neutrino mass of a few eV in flat models with cosmological constant ΩΛ= 1 - Ωm. We find that the possible improvement of the low-Ωm flat (LCDM) cosmological models with the addition of light neutrinos appears to be rather limited.