Neutrino spin oscillations in a magnetized Polish doughnut

TL;DR

This paper investigates how neutrino spin oscillations are affected by magnetic fields and matter in the environment of a rotating black hole with an accretion disk, predicting flux reductions and potential for magnetic field tomography.

Contribution

It provides a detailed analysis of neutrino spin oscillations in a magnetized accretion disk around a black hole, highlighting the dominant role of poloidal magnetic fields and matter interactions.

Findings

Toroidal magnetic fields do not significantly cause spin-flips.

Poloidal magnetic fields mainly modify neutrino flux.

Neutrino interactions with matter also affect flux.

Abstract

We study the gravitational scattering of ultrarelativistic neutrinos off a rotating supermassive black hole (BH) surrounded by a thick magnetized accretion disk. Neutrinos interact electroweakly with background matter and with the magnetic field in the disk since neutrinos are supposed to possess nonzero magnetic moments. The interaction with external fields results in neutrino spin oscillations. We find that the toroidal magnetic field, inherent in the magnetized Polish doughnut, does not cause a significant spin-flip for any reasonable strengths of the toroidal component. The reduction of the observed neutrino flux, owing to neutrino spin oscillations, is predicted. A poloidal component of the magnetic field gives the main contribution to the modification of the observed flux. The neutrino interaction with matter, rotating with relativistic velocities, also changes the flux of neutrinos. We briefly discuss the idea of the neutrino tomography of magnetic field distributions in accretion disks near BHs.