Testing 3+1 and 3+2 neutrino mass models with cosmology and short baseline experiments

Recent results from short-baseline neutrino oscillation experiments suggest the presence of additional sterile neutrinos, while cosmic microwave background anisotropy measurements point toward an excess of radiation, which could in fact be provided by light sterile neutrino states. In this paper we properly combine these two data sets (short-baseline and cosmic microwave background) to derive bounds on the sterile neutrino masses in the 3 + 1 and 3 + 2 schemes, finding a potentially good agreement between the two data sets. However, when data on galaxy clustering are further included in the analysis, a tension between the oscillation and cosmological data is clearly present. From our combined global analysis the allowed 95% C.L. mass intervals for the additional sterile neutrino states are: 0.85 eV < m(4) < 1.18 eV for the 3 + 1 scheme, and m(4) < 0: 70 eV and 0.67 eV < m(5) < 1.35 eV for the 3 + 2 scheme.