Hyperon Decays and QCD

Abstract

In a recent experiment in the CERN Super Proton Synchrotron (SPS) charged hyperon beam⁽¹⁾, 2400 Ω^- decays, about 20 times the previous world statistics, have been collected^¥. The analysis of the Ω^- sample has given an accurate measurement of the Ω^- lifetime⁽²⁾ [t_Ω- = (0.822 ± 0.028) × 10^-10 s] and the first determination of the Ω^- decay branching ratios⁽³⁾. In particular the measured ratio Γ(Ω^- → Ξ^oπ^-)/Γ(Ω^- → Ξ^-π^o) is 2.94 ± 0.35, while a pure ΔI = 1/2 amplitude would have given 2.03. A ratio of about 3 between those two decay modes had in fact been predicted by Finjord⁽⁴⁾ using the QCD framework.