Multi-G[CLC]e[/CLC]V Neutrinos from Internal Dissipation in Gamma-Ray Burst Fireballs

Abstract

Subphotospheric internal shocks and transverse differences of the bulk Lorentz factor in relativistic fireball models of gamma-ray bursts (GRBs) lead to neutron diffusion relative to protons, resulting in inelastic nuclear collisions. This results in significant fluxes of νμ(μ) of ~3 GeV and νe(e) of ~2 GeV, scaling with the flow Lorentz factor η < ηπ ~ 400. This extends significantly the parameter space for which neutrinos from inelastic collision are expected, which in the absence of the above effects requires values in excess of ηπ. A model with sideways diffusion of neutrons from a slower wind into a fast jet can lead to production of νμ(μ) and νe(e) in the range 2-25 GeV or higher, depending on the value of η. The emission from either of these mechanisms from GRBs at redshifts z ~ 1 may be detectable in suitably densely spaced detectors.