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Search for promptly produced heavy quarkonium states in hadronic Z decays

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Zeitschrift für Physik C Particles and Fields

Abstract

A search has been made for direct production of heavy quarkonium states in more than 3 million hadronicZ 0 decays in the 1991–1994 DELPHI data. PromptJ/ψ, ψ(2S) andΓ candidates have been searched for through their leptonic decay modes using criteria based on the kinematics and decay vertex positions. New upper limits are set at the 90% confidence level forBr(Z 0→(Qq)X)/Br(Z 0→ hadrons) for various strong production mechanisms ofJ/ψ andΓ; these range down to 0.9×10−4. The limits are set in the presence of a small excess (∼1% statistical probability of a background fluctuation) in the sum of candidates from promptJ/ψ, ψ(2S),γ(1S),γ(2S) andγ(3S) relative to the estimated background.

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DELPHI Collaboration., Abreu, P., Adam, W. et al. Search for promptly produced heavy quarkonium states in hadronic Z decays. Z. Phys. C - Particles and Fields 69, 575–583 (1995). https://doi.org/10.1007/BF02907441

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  • DOI: https://doi.org/10.1007/BF02907441

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