Transition Radiation by Neutrinos

TL;DR

This paper calculates the probability of neutrino transition radiation at media interfaces, considering standard-model couplings, and finds results significantly larger than previous estimates, with potential astrophysical implications.

Contribution

It provides an accurate, analytic calculation of neutrino transition radiation probabilities considering medium effects, improving upon prior estimates.

Findings

Transition radiation probability for 1 MeV neutrinos at polyethylene-vacuum interface is about 10^{-39}.

At neutron star surfaces, the probability may reach ~10^{-20}.

The results are three orders of magnitude larger than previous calculations.

Abstract

We calculate the transition radiation process $\nu \to \nu \gamma$ at an interface of two media. The neutrinos are taken to be with only standard-model couplings. The medium fulfills the dual purpose of inducing an effective neutrino-photon vertex and of modifying the photon dispersion relation. The transition radiation occurs when at least one of those quantities have different values in different media. The neutrino mass is ignored due to its negligible contribution. We present a result for the probability of the transition radiation which is both accurate and analytic. For $E_\nu =1$ MeV neutrino crossing polyethylene-vacuum interface the transition radiation probability is about $10^{-39}$ and the energy intensity is about $10^{-34}$ eV. At the surface of the neutron stars the transition radiation probability may be $\sim 10^{-20}$. Our result on three orders of magnitude is larger than the results of previous calculations.