Pulsar kicks from neutrino oscillations

TL;DR

This paper investigates whether pulsar natal kicks can originate from neutrino oscillations in a cooling neutron star. By analyzing two transport models—a hard neutrinosphere with a sharp boundary and a soft, diffusion-based atmosphere—it demonstrates that charged-current interactions, together with MSW resonances in a magnetized interior, can produce a momentum asymmetry sufficient to yield kicks of order $\Delta k/k \sim 10^{-2}$ for internal fields around $B \sim 10^{14}-10^{15}$ G. When absorptions are properly included, the two models converge on the same order of magnitude for the natal velocity, compatible with observed pulsar speeds of about $5\times10^2$ km s$^{-1}$. The work discusses implications for neutrino masses and beyond-Standard-Model scenarios, including keV-scale sterile neutrinos as dark matter and potential Majoron-related decay channels, highlighting how neutrino oscillations could be a robust explanation for pulsar kicks.

Abstract

Neutrino oscillations can explain the observed motion of pulsars. We show that two different models of neutrino emission from a cooling neutron star are in good quantitative agreement and predict the same order of magnitude for the pulsar kick velocity, consistent with the data.