Inflation models in the light of self-interacting sterile neutrinos

TL;DR

This study examines how self-interacting sterile neutrinos influence cosmological parameters and the viability of inflation models, showing that certain models are ruled out while others are favored based on CMB data analysis.

Contribution

It demonstrates that self-interacting sterile neutrinos significantly alter the spectral index and impact the viability of inflation models in cosmology.

Findings

Spectral index shifts to 0.9361 in SIν model

Starobinsky and quartic hilltop models are ruled out

Natural and Coleman-Weinberg inflation models are favored

Abstract

Short baseline neutrino experiments, like LSND and MiniBooNE experiments, pointed towards the existence of eV mass scale sterile neutrinos. To reconcile sterile neutrinos with cosmology self interaction between sterile neutrinos has been studied. We analysed Planck cosmic microwave background (CMB) data with self-interacting sterile neutrino (SI$\nu$) and study their impact on inflation models. The fit to the CMB data in SI$\nu$ model is as good as the fit to $\Lambda$CDM model. We find that the spectral index ($n_s$) values shift to $0.9361\pm 0.0055$ in SI$\nu$ model. This has significant impact on the validity of different inflation models. For example the Starobinsky and quartic hilltop model, which were allowed within $\Lambda$CDM cosmology, are ruled out. On the other hand some models like natural and Coleman-Weinberg inflation are now favoured. Therefore, the existence of self interacting sterile neutrinos with eV order of mass will play an important role in the selection of correct inflation model.