Nuclear β-decay and photoproduction of e + e − pairs in intense electromagnetic fields with a complex configuration

Abstract

The effect of an intense electromagnetic field formed by the superposition of a constant magnetic field and a laser-type field on nuclear β-decay and on pair production by two g-rays with different polarizations is studied. Time integral representations are obtained for the total probabilities of these processes without restrictions on the strengths of the fields making up the configuration. Despite the different nature of these reactions, in the nonrelativistic limitthese expressions contain similar dependences on the field characteristics and the differences reduce to different power-law singularities in the behavior of the integrands at zero. At low fields, complete asymptotic expansions of the probabilities of these processes, including perturbation theory terms and oscillatory field contributions, are obtained in terms of parameters characterizing the fields. It is shown that the oscillatory corrections can be enhanced owing to the effect of a combination external field. The analysis of the probabilities of the various processes given here in terms of nonlinear functions of the field is illustrated by numerical calculations and graphs.