Spin effects in neutrino gravitational scattering

TL;DR

This paper investigates how neutrino spins oscillate during gravitational scattering by black holes, revealing potential flux reductions and asymmetries influenced by black hole and accretion disk interactions.

Contribution

It derives analytical and numerical models for neutrino spin oscillations in black hole scattering, including effects of surrounding matter, which were not previously detailed.

Findings

Neutrino fluxes can decrease by nearly 20% due to spin oscillations.

Neutrino interactions with accretion disks cause asymmetries in outgoing fluxes.

Spin oscillations depend on impact parameter and environment conditions.

Abstract

We study spin oscillations of neutrinos gravitationally scattered off a nonrotating black hole (BH). We derive the transition and survival probabilities of spin oscillations in quadratures when neutrinos interacts with BH only. The dependence of the probabilities on the impact parameter is analyzed. Then, we obtain the effective Schr\"{o}dinger equation for neutrino spin oscillations in neutrino scattering off BH surrounded by background matter. This equation is solved numerically in the case of a supermassive BH with a realistic accretion disk. We find that the observed neutrino fluxes can be reduced almost 20% because of spin oscillations when neutrinos experience gravitational scattering. The neutrino interaction with an accretion disk results in the additional asymmetry in the intensities of outgoing fluxes depending on the neutrino trajectory.