Impact of radiative corrections on sterile neutrino scenarios

TL;DR

This paper examines how radiative corrections affect sterile neutrino models, finding that certain configurations are incompatible with observed data due to large mass splittings, while others remain stable.

Contribution

It provides a detailed analysis of the impact of radiative corrections on four-neutrino schemes, highlighting which configurations are theoretically viable.

Findings

Solar neutrino scheme with sterile component is disfavored due to large mass splitting.

Atmospheric neutrino scheme remains stable under radiative corrections.

Radiative effects are proportional to the top Yukawa coupling in sterile neutrino scenarios.

Abstract

In sterile neutrino scenarios, radiative corrections induce mass splittings proportional to the top Yukawa coupling, in contrast to the three active neutrino case where the induced splittings are proportional to the tau Yukawa coupling. In view of this, we have analyzed the stability of the four-neutrino schemes favored by oscillation experiments, consisting in two pairs of nearly degenerate neutrinos separated by the LSND gap. Requiring compatibility with the measurements of the abundances of primordial elements produced in Big Bang Nucleosynthesis, we find that when the heaviest pair corresponds to the solar neutrinos (mainly an admixture of nu_e - nu_s) the natural mass splitting is 3-5 orders of magnitude larger than the observed one, discrediting the scenario from a theoretical point of view. On the contrary, the scheme where the heaviest pair corresponds to the atmospheric neutrinos (mainly an admixture of nu_mu - nu_tau) is safe from radiative corrections due to the small sterile component of these mass eigenstates.