Scattering of neutrinos by a rotating black hole accounting for the electroweak interaction with an accretion disk

TL;DR

This paper investigates how ultrarelativistic neutrinos' spin and polarization are affected by gravitational, magnetic, and electroweak interactions when scattering off a rotating black hole with an accretion disk, highlighting potential observable effects.

Contribution

It provides an exact description of neutrino spin precession and polarization changes due to combined gravitational, magnetic, and electroweak interactions in a black hole environment.

Findings

Neutrino fluxes are affected by spin oscillations influenced by the accretion disk's matter.

Electroweak interactions with plasma alter neutrino polarization.

The study discusses the observability of these effects in astrophysical neutrinos.

Abstract

We study spin effects in the neutrino gravitational scattering by a supermassive black hole with a magnetized accretion disk having a finite thickness. We exactly describe the propagation of ultrarelativistic neutrinos on null geodesics and solve the spin precession equation along each neutrino trajectory. The interaction of neutrinos with the magnetic field is owing to the nonzero diagonal magnetic moment. Additionally, neutrinos interact with plasma of the accretion disk electroweakly within the Fermi approximation. These interactions are obtained to change the polarization of incoming neutrinos, which are left particles. The fluxes of scattered neutrinos, proportional to the survival probability of spin oscillations, are derived for various parameters of the system. In particular, we are focused on the matter influence on the outgoing neutrinos flux. The possibility to observe the predicted effects for astrophysical neutrinos is briefly discussed.