Pulsar acceleration by asymmetric emission of sterile neutrinos

Abstract

A convincing explanation for the observed pulsar large peculiar velocities is still missing. We argue that any viable particle physics solution would most likely involve the resonant production of a non-interacting neutrino $\nu_s$ of mass $m_{\nu_s}\sim 20$--50 keV. We propose a model where anisotropic magnetic field configurations strongly bias the resonant spin flavour precession of tau antineutrinos into $\nu_s$. For internal magnetic fields $B_{int} \gsim 10^{15}$ G a $\bar\nu_\tau$-$\nu_s$ transition magnetic moment of the order of $10^{-12}$ Bohr magnetons is required. The asymmetric emission of $\nu_s$ from the core can produce sizeable natal kicks and account for recoil velocities of several hundred kilometers per second.