title: Neutron-proton-converter acceleration mechanism at subphotospheres of relativistic outflows.
abstract: We study a type of particle acceleration that operates via neutron-proton conversion in inelastic nuclear collisions. This mechanism can be expected for relativistic shocks at subphotospheres if relativistic outflows contain neutrons. Using a test-particle approximation, we numerically calculate the energy spectrum and the efficiency of accelerated particles, and show that a good energy fraction of the nucleons can be accelerated. This mechanism may be especially relevant if the shock is radiation mediated, and it would enhance the detectability of GeV-TeV neutrinos.
authors.affiliation: Department of Astronomy and Astrophysics, Department of Physics, and Center for Particle and Gravitational Astrophysics, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Kazumi
authors.initials: K
authors.lastname: Kashiyama
authors.forename: Kohta
authors.initials: K
authors.lastname: Murase
authors.forename: Peter
authors.initials: P
authors.lastname: Mészáros