Direct comparison of sterile neutrino constraints from cosmological data, e disappearance data and μ→e appearance data in a 3+1 model
Abstract
We present a quantitative, direct comparison of constraints on sterile neutrinos derived from neutrino oscillation experiments and from Planck data, interpreted assuming standard cosmological evolution. We extend a 1+1 model, which is used to compare exclusions contours at the 95% CL derived from Planck data to those from e-disappearance measurements, to a 3+1 model. This allows us to compare the Planck constraints with those obtained through μ→e appearance searches, which are sensitive to more than one active-sterile mixing angle. We find that the cosmological data fully exclude the allowed regions published by the LSND, MiniBooNE and Neutrino-4 collaborations, and those from the gallium and rector anomalies, at the 95% CL. Compared to the exclusion regions from the Daya Bay e-disappearance search, the Planck data are more strongly excluding above | m241|≈ 0.1\, eV2 and meffsterile≈ 0.2\, eV, with the Daya Bay exclusion being stronger below these values. Compared to the combined Daya Bay/Bugey/MINOS exclusion region on μ→e appearance, the Planck data is more strongly excluding above m241≈ 5× 10-2\,eV2, with the exclusion strengths of the Planck data and the Daya Bay/Bugey/MINOS combination becoming comparable below this value.