Semi-classical calculation of the number of photons emitted by a relativistic neutrino with mass and magnetic moment passing through a transverse magnetic field

A classical calculation, modified by Compton-recoil kinematics, of the radiation emitted by a relativistic neutrino with mass and a magnetic moment passing through a transverse magnetic field. The calculation is performed in the neutrinos rest frame by the method of virtual quanta. The total number N of virtual quanta scattered by the neutrino is determined. The semi-classical result for the analog of the Klein-Nishina formula is compared with a QED calculation of the photon scattering cross section. The different angular distributions, both strongly peaked, lead to a factor of two difference between the QED and semi-classical results for N.