Massive neutrino decay νi → νiγ in a crossed field

Radiative decay of the massive neutrino νi→νiγ (mi>mj) in a constant crossed electromagnetic field is investigated within the framework of the standard electroweak theory. It is shown that the decay is catalyzed by the external field. This effect becomes significant in a strong crossed field (F much-gt Be = m2e/e ≅ 4.41 x 1013 G) and event more pronounced for the ultrarelativistic neutrino (Eν much-gt mν) in a relatively weak field (F much-lt Be). 11 refs., 1 fig