Neutrino Pair Annihilation above Black Hole Accretion Disks in Modified Gravity

Using idealized models of the accretion disk, we investigate the effects induced by the modified theories of gravity on the annihilation of the neutrino pair annihilation into electron-positron pairs ( nu(nu) over bar -> e(-) e(+) ), occurring near the rotational axis. For the accretion disk, we have considered the models with temperature T = constant and T proportional to r (-1). In both cases, we find that the modified theories of gravity lead to an enhancement, up to more than 1 order of magnitude with respect to general relativity, of the neutrino pair annihilation.