Spin oscillations of neutrinos scattered off a rotating black hole

TL;DR

This paper investigates how neutrino spin oscillations occur when neutrinos are gravitationally scattered by rotating and nonrotating black holes, deriving probabilities and analyzing their impact on neutrino fluxes in astrophysical contexts.

Contribution

The study provides analytic expressions for neutrino spin oscillation probabilities in black hole gravitational fields, including effects of rotation and surrounding matter, with numerical analysis for supermassive black holes.

Findings

Spin oscillations are negligible in Schwarzschild black holes.

In Kerr black holes, neutrino fluxes can decrease by nearly 10% due to spin oscillations.

Neutrino interactions with accretion disks further modify flux intensities.

Abstract

Spin oscillations of neutrinos, gravitationally scattered off a black hole (BH), are studied. The cases of nonrotating and rotating BHs are analyzed. We derive the analytic expressions for the transition and survival probabilities of spin oscillations when neutrinos interact with these gravitational backgrounds. The obtained transition probabilities depend on the impact parameter, as well as the neutrino energy and the particle mass. We find that there is a possibility of spin oscillations of ultrarelativistic neutrinos scattering off a rotating BH. Then, considering the neutrino scattering off BH surrounded by background matter, we derive the effective Schrodinger equation for spin oscillations. The numerical solution of this equation is obtained in the case of a supermassive BH with a realistic accretion disk. Spin effects turn out to be negligible in the neutrino scattering in the Schwarzschild metric. In the Kerr metric, we find that the observed neutrino fluxes can be reduced almost 10% because of spin oscillations when ultrarelativistic neutrinos experience gravitational scattering. The neutrino interaction with an accretion disk results in the additional modification of the intensities of outgoing neutrino fluxes. We consider the applications of the obtained results for the neutrino astronomy.