Flavor ratios of astrophysical neutrinos interacting with stochastic gravitational waves having arbitrary spectra

TL;DR

This paper investigates how stochastic gravitational waves with arbitrary spectra influence the flavor oscillations of astrophysical neutrinos, providing analytical and numerical solutions for different scenarios and discussing observational implications.

Contribution

It derives a general density matrix evolution equation for neutrinos interacting with stochastic GWs and solves it analytically for two flavors and numerically for three flavors, considering realistic GW sources.

Findings

Analytical solution for two-flavor neutrino oscillations in stochastic GWs.

Numerical analysis of three-flavor neutrino evolution with realistic GW spectra.

Identification of energy and distance ranges where flux relaxation is significant.

Abstract

We study the evolution and oscillations of fixed massive neutrinos interacting with stochastic gravitational waves (GWs). The energy spectrum of these GWs is Gaussian, with the correlator of the amplitudes being arbitrary. We derive the equation for the density matrix for flavor neutrinos in this case. In the two flavors approximation, this equation can be solved analytically. We find the numerical solution for the density matrix in the general case of three neutrino flavors. We consider merging binary black holes as sources of stochastic GWs with realistic spectra. Both normal and inverted mass orderings are analyzed. We discuss the relaxation of the neutrino fluxes in stochastic GWs emitted mainly by supermassive black holes. In this situation, we obtain the range of energies and the propagation lengths for which the relaxation process is the most efficient. We discuss the application of our results for the observation of fluxes of astrophysical neutrinos.