2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/45363Corrections $\sim α^2 $ to the positronium decay rate, induced by one--loop vacuum polarization diagram, are calculated. Their relative values are $0.4468(3)(α/π)^2$ for para- and $0.960(3)(α/π)^2$ for orthopositronium.10 pages, LaTeXHigh Energy Physics - Phenomenologytext