Neutrino Spin-Flavor Conversions and Electron Antineutrino emission from the Sun with Random Magnetic Field

TL;DR

This paper investigates how random magnetic fields in the Sun's convective zone influence neutrino spin-flavor conversions, potentially producing electron antineutrinos and altering the allowed neutrino oscillation parameters.

Contribution

It introduces a model considering random magnetic fields' effects on neutrino conversions, revealing new possible neutrino behaviors and constraints from experimental data.

Findings

Random magnetic fields can produce electron antineutrinos in the Sun.

Certain neutrino oscillation parameter regions may be excluded by this mechanism.

The LOW MSW region remains allowed under specific magnetic field conditions.

Abstract

The magnetic field in the solar convective zone has a random small-scale component with the r.m.s. value substancially exceeding the strength of a regular large-scale field. For two Majorana neutrino flavors and two helicities in the presence of a neutrino transition magnetic moment and nonzero neutrino mixing we analize the displacement of the allowed (Delta m^2 - sin^2 2theta)-parameter region reconciled for all Underground experiments with solar neutrinos in dependence on the r.m.s. magnetic field value b. In contrary with the RSFP scenario with a regular large-scale magnetic field, we find an effective production of electron antineutrinos in the Sun even for small neutrino mixing through the cascade conversions like nu_eL -> \bar{nu}_muR -> \bar{nu}_eR. It was found that usual SMA and LMA MSW parameter regions maybe forbidden while opening LOW MSW as the allowed one from the non-observation of \bar{nu}_eR in the SK experiment if random magnetic fields have strengths b > 100 kG and correlation lengths shorter than L_0 < 1000 km.