Direct URCA Processes in Supernovae and Accretion Disks with Arbitrary Magnetic Field

Abstract

An effect of a magnetic field of an arbitrary strength on the beta-decay and reactions related with it by the crossing symmetry (the beta-processes) in supernovae and accretion disks around black holes is analyzed. Rates of the beta-processes and the energy and momentum transfered through them to an optically transparent matter are calculated. It is shown that the macroscopic momentum transferred to the medium increases linearly with the magnetic field strength and can substantially affect the dynamics of supernovae and accretion disks especially when a matter inside is degenerate. It is also demonstrated that the rates of the beta-processes and the energy deposition in these reactions for the magnetic field strength B 1015 G, which is assumed to be typical in supernovae and accretion disks, are lower than in the absence of the field. This suppression is more pronounced for reactions with neutrinos.