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Probing Unstable Massive Neutrinos with Current Cosmic Microwave Background Observations

1998; American Physical Society; Volume: 81; Issue: 15 Linguagem: Inglês

10.1103/physrevlett.81.3075

1092-0145

Robert E. Lopez, Scott Dodelson, Robert J. Scherrer, Michael S. Turner,

Dark Matter and Cosmic Phenomena

The pattern of anisotropies in the cosmic microwave background depends upon the masses and lifetimes of the three neutrino species. A neutrino species of mass greater than 10 eV with lifetime between ${10}^{13}$ and ${10}^{17}\mathrm{sec}$ leaves a very distinct signature (due to the integrated Sachs-Wolfe effect): the anisotropies at large angles are predicted to be comparable to those on degree scales. Present data exclude such a possibility and hence this region of parameter space. For ${m}_{\ensuremath{\nu}}\ensuremath{\simeq}30\mathrm{eV}$, $\ensuremath{\tau}\ensuremath{\simeq}{10}^{13}\mathrm{sec}$, we find an interesting possibility: the integrated Sachs-Wolfe peak produced by the decaying neutrino in low- $\ensuremath{\Omega}$ models mimics the acoustic peak expected in an $\ensuremath{\Omega}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1$ model.