Matter Effects in Solar Neutrino Active-Sterile Oscillations

TL;DR

This paper investigates how matter influences solar neutrino oscillations involving active and sterile neutrinos, providing a general analysis applicable to various models and confirming results with numerical simulations.

Contribution

It offers a comprehensive analysis of matter effects in solar neutrino oscillations without restrictions on sterile neutrino parameters, extending previous models.

Findings

Analytic expressions for matter effects in general sterile-active neutrino mixing

Numerical validation using a four-neutrino mixing model

Insights into the role of matter in neutrino oscillation dynamics

Abstract

We study the matter effects for solar neutrino oscillations in a general scheme, without any constraint on the number of sterile neutrinos and the mixing matrix elements, only assuming a realistic hierarchy of neutrino squared-mass differences in which the smallest squared-mass difference is effective in solar neutrino oscillations. The validity of the analytic results are illustrated with a numerical solution of the evolution equation in the simplest case of four-neutrino mixing with the realistic matter density profile inside the Sun.