6533b85afe1ef96bd12b981e

RESEARCH PRODUCT

Sterile neutrino models and nonminimal cosmologies

subject

description

Cosmological measurements are affected by the energy density of massive neutrinos. We extend here a recent analysis of current cosmological data to nonminimal cosmologies. Several possible scenarios are examined: a constant $w\ensuremath{\ne}\ensuremath{-}1$ dark energy equation of state, a nonflat universe, a time-varying dark energy component and coupled dark matter-dark energy universes or modified gravity scenarios. When considering cosmological data only, ($3+2$) massive neutrino models with $\ensuremath{\sim}0.5\text{ }\text{ }\mathrm{eV}$ sterile species are allowed at 95% confidence level. This scenario has been shown to reconcile reactor, LSND and MiniBooNE positive signals with null results from other searches. Big bang nucleosynthesis bounds could compromise the viability of ($3+2$) models if the two sterile species are fully thermalized states at decoupling.