Enhancement of the ν̄e flux from astrophysical sources by two-photon annihilation interactions

The ratio of antielectron to total neutrino flux, Φν̄e Φν, expected from pγ interactions in astrophysical sources is ≤1 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 Φν̄e Φν ratio may be significantly enhanced in gamma-ray burst (GRB) fireballs, and that detection at the Glashow resonance of ν̄e in kilometer scale neutrino detectors may constrain GRB fireball model parameters, such as the magnetic field and energy dissipation radius.