400 research outputs found
Neutrino mass eigenstates and their ordering: a Bayesian approach
One of the not-yet determined properties of neutrinos is the ordering of
their mass eigenstates. We combine the available data from neutrino
oscillations, neutrinoless double beta decay and Cosmic Microwave Background
observations to derive robust constraints on the mass ordering in a Bayesian
context. Based on arxiv:1801.04946.Comment: 3 pages, 2 figures. To appear in the Proceedings of Incontri di
Fisica delle Alte Energie (IFAE) 201
Light sterile neutrinos and inflationary freedom
We perform a cosmological analysis in which we allow the primordial power spectrum of scalar perturbations to assume a shape that is different from the usual power-law predicted by the simplest models of cosmological inflation. We parameterize the free primordial power spectrum with a ``piecewise cubic Hermite interpolating polynomial'' (PCHIP). We consider a 3+1 neutrino mixing model with a sterile neutrino having a mass at the eV scale, which can explain the anomalies observed in short-baseline neutrino oscillation experiments. We find that the freedom of the primordial power spectrum allows to reconcile the cosmological data with a fully thermalized sterile neutrino in the early Universe. Moreover, the cosmological analysis gives us some information on the shape of the primordial power spectrum, which presents a feature around the wavenumber k=0.002 Mpc 121
Light Sterile Neutrinos and Inflationary Freedom
We perform a cosmological analysis in which we allow the primordial power
spectrum of scalar perturbations to assume a shape that is different from the
usual power-law predicted by the simplest models of cosmological inflation. We
parameterize the free primordial power spectrum with a "piecewise cubic Hermite
interpolating polynomial" (PCHIP). We consider a 3+1 neutrino mixing model with
a sterile neutrino having a mass at the eV scale, which can explain the
anomalies observed in short-baseline neutrino oscillation experiments. We find
that the freedom of the primordial power spectrum allows to reconcile the
cosmological data with a fully thermalized sterile neutrino in the early
Universe. Moreover, the cosmological analysis gives us some information on the
shape of the primordial power spectrum, which presents a feature around the
wavenumber .Comment: 19 pages; corrected Fig.4 and added Ref.[35
Light Sterile Neutrinos in Cosmology and Short-Baseline Oscillation Experiments
We analyze the most recent cosmological data, including Planck, taking into
account the possible existence of a sterile neutrino with a mass at the eV
scale indicated by short-baseline neutrino oscillations data in the 3+1
framework. We show that the contribution of local measurements of the Hubble
constant induces an increase of the value of the effective number of
relativistic degrees of freedom above the Standard Model value, giving an
indication in favor of the existence of sterile neutrinos and their
contribution to dark radiation. Furthermore, the measurements of the local
galaxy cluster mass distribution favor the existence of sterile neutrinos with
eV-scale masses, in agreement with short-baseline neutrino oscillations data.
In this case there is no tension between cosmological and short-baseline
neutrino oscillations data, but the contribution of the sterile neutrino to the
effective number of relativistic degrees of freedom is likely to be smaller
than one. Considering the Dodelson-Widrow and thermal models for the
statistical cosmological distribution of sterile neutrinos, we found that in
the Dodelson-Widrow model there is a slightly better compatibility between
cosmological and short-baseline neutrino oscillations data and the required
suppression of the production of sterile neutrinos in the early Universe is
slightly smaller.Comment: 12 pages; final version published in JHEP 1311 (2013) 21
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