Light Sterile Neutrinos and Inflationary Freedom

Abstract

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 $k=0.002{\text{Mpc}}^{-1}$.

19 pages; corrected Fig.4 and added Ref.[35]

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Cited by in corpus (3)

• Constraints on sterile neutrinos and the cosmological tensions
• Constraining the Effective Mass of Majorana Neutrino with Sterile Neutrino Mass for Inverted Ordering Spectrum
• Robustness of cosmological axion mass limits