2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/40657We analyze the spectrum of the ultrahigh energy (above \approx 10^{9} GeV) cosmic rays. With a maximum likelihood analysis we show that the observed spectrum is consistent with the decay of extragalactic GUT scale particles. The predicted mass for these superheavy particles is m_X=10^b GeV, where b=14.6_{-1.7}^{+1.6}.4 pages, 3 figures, talk to be presented at the 27th International Cosmic Ray Conference, Hamburg, Germany, August 7-15, 2001High Energy Physics - PhenomenologyAstrophysicstext