Fermi-Dirac correlations in Λ pairs in hadronic Z decays
R Barate, D Decamp, P Ghez, C Goy, JP Lees, F Martin, E Merle, MN Minard, B Pietrzyk, R Alemany, S Bravo, MP Casado, M Chmeissani, JM Crespo, E Fernandez, M Fernandez-Bosman, L Garrido, E Graugès, A Juste, M Martinez Show all
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Published : 2000
Two-particle correlations of ΛΛ and ΛΛ pairs have been studied in multihadronic Z decays recorded with the ALEPH detector at LEP in the years from 1992 to 1995. The correlations were measured as a function of the four-momentum difference Q of the pair. A depletion of events is observed in the region Q2 GeV the fraction of pairs with spin one is consistent with the value of 0.75 expected for a statistical spin mixture, whilst for Q>2 GeV this fraction is found to be lower. For ΛΛ 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. © 2000 Elsevier Science B.V.