2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/49645We briefly review the theoretical and experimental results concerning decays of positronium. Possible solutions of the "orthopositronium lifetime puzzle" are discussed. Positronium annihilation into neutrinos is examined and disagreement is found with previously published results.Talk given at the 14th International Workshop on High Energy Physics and Quantum Field Theory (QFTHEP99), May 1999, Moscow, Russia, to appear in the Proceedings; 9 pages, latexHigh Energy Physics - Phenomenologytext