Feynman path integral method and Landau-Pomeranchuk-Migdal effect for finite targets

A Feynman path integral formalism for treating the suppression of bremsstrahlung radiation of long-wavelength photons, the Landau-Pomeranchuk-Migdal (LPM) effect, in a target of finite thickness with multiple scattering is developed. Taking into account the side effect yields corrections to the Migdal theory. The method is also applied to the treatment of the standard LPM effect in the presence of an external field.