Scattering of massive neutrino test fields from a gravitational pulse

TL;DR

This study analyzes the propagation of a massive neutrino field through localized gravitational pulses modeled as sandwich-plane waves in Einstein–Maxwell theory. The authors solve the Weyl equation for a massive Majorana neutrino in a Rosen-form spacetime, obtaining exact plane-wave solutions with a region-dependent phase $K(u)$ and matching them across the wave using O'Brien–Synge junction conditions, yielding explicit metric profiles $F(u)$ and $G(u)$ for three backgrounds: purely gravitational, purely electromagnetic, and a gravitational–electromagnetic mix. They compute the neutrino energy density $\rho$ and the energy change $\Delta\rho$ across the wave, showing energy exchange between the neutrino and the wave and energy/phase variations that depend on the momenta $(p_v,p_1,p_2)$ and Grassmann parameters $|\eta_1|^2$, $|\eta_2|^2$. The results suggest possible implications for neutrino oscillations in curved spacetime and motivate future work extending to at least two neutrino species to explore flavor dynamics in gravitational backgrounds.

Abstract

Linearized Einstein-Weyl equations are solved precisely in the context of sandwich gravitational waves. The neutrino's energy-momentum depends on the geometry and composition of the gravitational pulse when it is scattered. Since the background remains unchanged at the test field level, the neutrino's energy density will exhibit fluctuations between positive and negative extremes when traversing the sandwich wave. These variations could provide insights into the behavior of models concerning neutrino oscillations.

Figures (1)

• Figure 1: The general structure of the gravitational sandwich wave geometry consists of three regions. Region I represents the flat Minkowski spacetime ahead of the sandwich wave. Region II is the curved domain where the sandwich wave is present. Region III corresponds to the flat Minkowski region trailing the wave.