# Fermi-Dirac Correlations in $\Lambda$ Pairs in Hadronic Z Decays

Abstract : Two-particle correlations of Lambda Lambda and Anti-Lambda Anti-Lambda pairshave 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 Q 2 GeV which could arise from the effects of Fermi-Dirac statistics. In addition the spin content of the Lambda pair system has been determined. For Q 2 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 Lambda Anti-Lambda 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.
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Journal articles

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Submitted on : Tuesday, April 4, 2000 - 11:01:21 AM
Last modification on : Sunday, June 26, 2022 - 11:42:32 AM
Long-term archiving on: : Friday, May 29, 2015 - 4:46:02 PM

### Identifiers

• HAL Id : in2p3-00004624, version 1

### Citation

R. Barate, D. Decamp, P. Ghez, C. Goy, J.P. Lees, et al.. Fermi-Dirac Correlations in $\Lambda$ Pairs in Hadronic Z Decays. Physics Letters B, Elsevier, 2000, 475, pp.395-406. ⟨in2p3-00004624⟩

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