2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/56159Three-photon vertex in a dense degenerated plasma is calculated. It is discovered the polarization tensor has the longitudinal part which makes possible an interaction between transverse and longitudinal modes in the medium. Using dispersion relations it is shown that the only kinematically permitted type of the photon splitting is the decay of the transverse photon to two plasmons.11 pages, 2 EPS figuresHigh Energy Physics - Theorytext