Neutrinos and Gamma Rays from Photomeson Processes in Gamma Ray Bursts

Acceleration of high-energy hadrons in GRB blast waves will be established if highenergy neutrinos are detected from GRBs. Recent calculations of photomeson neutrino production are reviewed, and new calculations of high-energy neutrinos and the accompanying hadronic cascade radiation are presented. If hadrons are injected in GRB blast waves with an energy corresponding to the measured hard X-ray/soft γ-ray emission, then only the most powerful bursts at fluence levels > ∼ 3×10 −4 ergcm−2 offer a realistic prospect for detection of νμ . Detection of high-energy neutrinos are likely if GRB blast waves have large baryon loads and Doppler factors < ∼ 200. Significant limitations on the hadronic baryon loading and the number of expected neutrinos are imposed by the fluxes from pair-photon cascades initiated in the same processes that produce neutrinos.