Are Light Sterile Neutrinos Preferred or Disfavored by Cosmology?
  We find that the viability of a cosmological model that incorporates 2
sterile neutrinos with masses around 1 eV each, as favored by global neutrino
oscillation analyses including short baseline results, is significantly
dependent on the choice of datasets included in the analysis and the ability to
control the systematic uncertainties associated with these datasets. Our
analysis includes a variety of cosmological probes including the cosmic
microwave background (WMAP7+SPT), Hubble constant (HST), galaxy power spectrum
(SDSS-DR7), and supernova distances (SDSS and Union2 compilations). In the
joint observational analysis, our sterile neutrino model is equally favored as
a LCDM model when using the MLCS light curve fitter for the supernova
measurements, and strongly disfavored by the data at \Delta\chi^2 ~ 18 when
using the SALT2 fitter. When excluding the supernova measurements, the sterile
neutrino model is disfavored by the other datasets at \Delta\chi^2 ~ 12, and at
best becomes mildly disfavored at \Delta\chi^2 ~ 3 when allowing for curvature,
evolving dark energy, additional relativistic species, running of the spectral
index, and freedom in the primordial helium abundance. No single additional
parameter accounts for most of this effect. Therefore, if laboratory
experiments continue to favor a scenario with roughly eV mass sterile
neutrinos, and if this becomes decisively disfavored by cosmology, then a more
exotic cosmological model than explored here may become necessary.
