Matter-affected neutrino oscillations in ordinary and mirror stars and their implications for gamma-ray bursts

It has been proposed that the annihilation process vv -> e- e+-> (gamma) (gamma)may be responsible for the generation of gamma-ray bursts (GRBs). The incipient neutrino-antineutrino pairs carry virtually all of the gravitational binding energy available from the central engine. However, gamma-ray bursters proposed to date are inevitably surrounded by an excess of baryons, leading to the "baryon-loading problem". In the light of growing evidence for neutrino oscillations, we discuss the implications of matter-affected oscillations for GRB energetics, and on the viability of "mirror" stars as GRB progenitors.