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G.J. Mathews (Univ. Notre Dame), M. Orito, T. Kajino (NAO, Japan), Y. Wang (U. Oklahoma)
We reanalyze the cosmological constraints on the existence of a net universal lepton asymmetry and neutrino degeneracy based upon the latest high resolution CMB sky maps from BOOMERANG, DASI, and MAXIMA-1. We compute likelihood functions for flat cosmological models with and without degenerate neutrinos. We adopt priors on the degeneracy parameters and baryon content based upon light-element constraints on primordial nucleosynthesis. We also adopt the prior of h = 0.72 ±0.08 from the Hubble Key Project results. Our neutrino-degenerate CMB models include a correction for that change in neutrino decoupling temperature with degeneracy. The marginalized likelihood functions show a slight preference for a neutrino-degenerate universe.