Resonance refraction and neutrino oscillations

TL;DR

This paper investigates how resonance effects in neutrino refraction influence oscillation probabilities, revealing new resonance phenomena, their implications for neutrino properties, and constraints from experimental data.

Contribution

It introduces a detailed analysis of resonance refraction effects on neutrino oscillations, including new MSW resonances and bounds on neutrino-background interactions.

Findings

Resonance refraction causes a bump in oscillation probability.

Background interactions shift and create new MSW resonances.

MiniBooNE excess cannot be explained by resonance refraction.

Abstract

The refraction index and matter potential depend on neutrino energy and this dependence has a resonance character associated to the production of the mediator in the $s-$channel. For light mediators and light particles of medium (background) the resonance can be realized at energies accessible to laboratory experiments. We study properties of the energy dependence of the potential for different C-asymmetries of background. Interplay of the background potential and the vacuum term leads to (i) bump in the oscillation probability in the resonance region, (ii) dip related to the MSW resonance in the background, (iii) substantial deviation of the effective $\Delta m^2$ above the resonance from the low energy value, etc. We considered generation of mixing in the background. Interactions with background shifts the energy of usual MSW resonance and produces new MSW resonances. Searches of the background effects allow us to put bounds on new interactions of neutrinos and properties of the background. We show that explanation of the MiniBooNE excess, as the bump due to resonance refraction, is excluded.