par Abreu, Pedro;Bertrand, Daniel ;Vander Velde, Catherine ; [et al.]
Référence Physics letters. Section B, 398, page (207-222)
Publication Publié, 1997
Article révisé par les pairs
Résumé : In a sample of 3.02 million hadronic Z0 decays collected by the DELPHI detector, 270 J/ψ → l+l- candidates have been selected. A search for fully reconstructed B±c mesons has yielded one B±c → J/ψ π± candidate, no B±c → J/ψ l± Vl candidates, and one B±c → J/ ψ π+ π- π± candidate, consistent with expected background in each channel. The following 90% confidence level upper limits are determined: Br(Z0 → B±c X) × Br(B±c → J/ψ π±) < (1.05 to 0.84) × 10-4 and Br(Z0 → B±c X) × Br(B±c → J/ψ l± Vl) < (5.8 to 5.0) × 10-5, where the ranges quoted correspond to the range of predicted B±c lifetimes from 0.4 to 1.4 ps, and Br(Z0 → B±c X) × Br(B±c → J/ψ π+ π- π±) < 1.75 × 10-4, constant over the range of predicted B±c lifetimes. © 1997 Elsevier Science B.V.