Gravitational helicity interaction

TL;DR

This paper investigates how gravitational interactions affect massless particles with different helicities, revealing helicity-dependent deflections and providing corrected scattering cross sections within general relativity.

Contribution

It introduces a correction to the geometric optics approximation accounting for helicity effects in gravitational deflections of massless particles.

Findings

Helicity influences gravitational deflection angles.

Derived scattering cross sections for neutrinos, photons, and gravitons.

Discussed the validity range of the Born approximation.

Abstract

For gravitational deflections of massless particles of given helicity from a classical rotating body, we describe the general relativity corrections to the geometric optics approximation. We compute the corresponding scattering cross sections for neutrinos, photons and gravitons to lowest order in the gravitational coupling constant. We find that the helicity coupling to spacetime geometry modifies the ray deflection formula of the geometric optics, so that rays of different helicity are deflected by different amounts. We also discuss the validity range of the Born approximation.