2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/43897We analyze the end-point region of the photon spectrum in semi-inclusive radiative decays of very heavy quarkonium (m alpha_s^2 >> Lambda_QCD). The S- and P-wave octet shape functions are calculated. When they are included in the analysis of the photon spectrum of the Upsilon (1S) system the agreement with data becomes excellent.4 pages, 2 figures, talk given at Quark Confinement and the Hadron Spectrum VI, to appear in the proceedingsHigh Energy Physics - PhenomenologyHigh Energy Physics - Experimenttext