Search for sterile neutrinos in a universe of vacuum energy interacting with cold dark matter

Publication date: Available online 3 January 2019Source: Physics of the Dark UniverseAuthor(s): Lu Feng, Jing-Fei Zhang, Xin ZhangAbstractWe investigate the cosmological constraints on sterile neutrinos in a universe in which vacuum energy interacts with cold dark matter by using latest observational data. We focus on two specific interaction models, Q=βHρv and Q=βHρc. To overcome the problem of large-scale instability in the interacting dark energy scenario, we employ the parametrized post-Friedmann (PPF) approach for interacting dark energy to do the calculation of perturbation evolution. The observational data sets used in this work include the Planck 2015 temperature and polarization data, the baryon acoustic oscillation measurements, the type-Ia supernova data, the Hubble constant direct measurement, the galaxy weak lensing data, the redshift space distortion data, and the Planck lensing data. Using the all-data combination, we obtain Neff<3.522 and mν,sterileeff<0.576eV for the Q=βHρv model, and Neff=3.204−0.135+0.049 and mν,sterileeff=0.410−0.330+0.150eV for the Q=βHρc model. The latter indicates ΔNeff>0 at the 1.17σ level and a nonzero mass of sterile neutrino at the 1.24σ level. In addition, for the Q=βHρv model, we find that β=0 is consistent with the current data, and for the Q=βHρc model, we find that β>0 is obtained at more than 1σ level.

Source: Physics of the Dark Universe - January 4, 2019 Category: Physics Source Type: research