Are light sterile neutrinos preferred or disfavored by cosmology?

作者：Joudaki Shahab^*; Abazajian Kevork N; Kaplinghat Manoj

来源：Physical Review D - Particles, Fields, Gravitation and Cosmology, 2013, 87(6): 065003.

DOI：10.1103/PhysRevD.87.065003

We find that the viability of a cosmological model that incorporates two 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 data sets included in the analysis and the ability to control the systematic uncertainties associated with these data sets. 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 Lambda CDM model when using the MLCS light curve fitter for the supernova measurements, and strongly disfavored by the data at Delta chi(2)(eff) approximate to 18 when using the SALT2 fitter. When excluding the supernova measurements, the sterile neutrino model is disfavored by the other data sets at Delta chi(2)(eff) approximate to 12, and at best becomes mildly disfavored at Delta chi(2)(eff) approximate to 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. DOI: 10.1103/PhysRevD.87.065003

• 出版日期2013-3-5