Fermi–Dirac correlations in Λ pairs in hadronic Z decays

Abstract Two-particle correlations of ΛΛ and Λ Λ pairshave been studied in multihadronic Z decays recorded with the ALEPHdetector at LEP in the years from 1992 to 1995. The correlations were measured as a function of the four-momentumdifference Q of the pair. A depletion of events is observed in the region Q Λ pairsystem has been determined. For Q >2 GeV the fraction of pairswith spin one is consistent with the value of 0.75 expected for a statistical spin mixture, whilst for Q Λ Λ pairs, where no Fermi–Dirac correlations are expected, the spin one fraction is measured to be consistent with 0.75 over the entire analysed Q range.