Neutrino oscillations in gravitational waves

TL;DR

This paper investigates how gravitational waves influence neutrino spin and flavor oscillations, revealing potential resonance effects and implications for cosmic neutrino detection.

Contribution

It derives new equations describing neutrino oscillations in curved spacetime with gravitational waves and explores their astrophysical implications.

Findings

Parametric resonance can occur in neutrino spin oscillations due to gravitational waves.

Neutrino flavor oscillation equations are solved in stochastic GW backgrounds.

Predicted neutrino fluxes could be detected by terrestrial experiments.

Abstract

We study spin and flavor oscillations of neutrinos under the influence of gravitational waves (GWs). We rederive the quasiclassical equation for the evolution of the neutrino spin in various external fields in curved spacetime starting from the Dirac equation for a massive neutrino. Then, we consider neutrino spin oscillations in nonmoving and unpolarized matter, a transverse magnetic field, and a plane GW. We show that a parametric resonance can take place in this system. We also study neutrino flavor oscillations in GWs. The equation for the density matrix of flavor neutrinos is solved when we discuss the neutrino interaction with stochastic GWs emitted by coalescing supermassive black holes. We find the fluxes of cosmic neutrinos, undergoing flavor oscillations in such a gravitational background, which can be potentially measured by a terrestrial detector. Some astrophysical applications of our results are considered.