2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/190331The decays of a scalar particle, of either parity, into two photons or into two gravitons are evaluated. The effective interactions are of the form $ϕFF, ϕF\tilde{F}$ or $ϕRR,ϕR\tilde{R}$; in particular, Higgs boson decay into gravitons cannot be adduced to an interaction $ϕR$, as has been recently claimed.7 pages and 1 figure, RevTex. axodraw.sty needed for the figureHigh Energy Physics - Phenomenologytext