Enhancement of the $\barν_e$ flux from astrophysical sources by two photon annihilation interactions

Abstract

The ratio of anti-electron to total neutrino flux, $Φ_{\barν_e}:Φ_ν$, expected from $pγ$ interactions in astrophysical sources is $\le1:15$. We point out that this ratio is enhanced by the decay of $μ^+μ^-$ pairs, created by the annihilation of secondary high energy photons from the decay of the neutral pions produced in $pγ$ interactions. We show that, under certain conditions, the $Φ_{\barν_e}:Φ_ν$ ratio may be significantly enhanced in gamma-ray burst (GRB) fireballs, and that detection at the Glashow resonance of $\barν_e$ in kilometer scale neutrino detectors may constrain GRB fireball model parameters, such as the magnetic field and energy dissipation radius.