Neutrino oscillations in nuclear media

TL;DR

This paper develops an effective Hamiltonian to study how nuclear media and magnetic fields influence neutrino oscillations, revealing modifications to mixing parameters and oscillation patterns, especially at high energies.

Contribution

It introduces a new effective Hamiltonian for neutrinos in nuclear media, accounting for magnetic fields, and analyzes their impact on neutrino oscillation parameters and phenomena.

Findings

Neutrino mixing angle and mass squared difference are modified in nuclear media.

High-energy neutrino oscillations are suppressed in nuclear media.

Resonance and level-crossing phenomena are discussed in the context of nuclear media.

Abstract

On basis of effective interactions of charged lepton and hadron currents, we obtain an effective interacting Hamiltonian of neutrinos in nuclear media up to the leading order. Using this effective Hamiltonian, we study neutrino mixing and oscillations in nuclear media and strong magnetic fields. We compute neutrino mixing angle and mass squared difference, and find the pattern of vacuum neutrino oscillations is modified in magnetized nuclear media. Comparing with the vacuum neutrino oscillation, we find that for high-energy neutrinos, neutrino oscillations are suppressed in the presence of nuclear media. In the general case of neutral nuclear media with the presence of electrons, we calculate the mixing angle and mass squared difference, and discuss the resonance and level-crossing in neutrino oscillations.