PLASMA INDUCED FERMION SPIN–FLIP CONVERSION fL → fR + γ

The fermion spin–flip conversion fL → fR + γ is considered, caused by the difference of the additional energies of the electroweak origin, acquired by left- and right-handed fermions (neutrino, electron) in medium. An accurate analysis of the fermion and photon dispersion in medium is performed. It is shown that the threshold arises in the process, caused by the photon (plasmon) effective mass. This threshold leaves no room for the so-called "spin light of neutrino" and "spin light of electron" in the real astrophysical situations.