Evidence for b baryons in Z decays

D Decamp; B Deschizeaux; C Goy; JP Lees; MN Minard; R Alemany; F Ariztizabal; JM Crespo; M Delfino; E Fernandez; V Gaitan; L Garrido; LM Mir; A Pacheco; A Pascual; MG Catanesi; D Creanza; M de Palma; A Farilla; G Iaselli; G Maggi; M Maggi; S Natali; S Nuzzo; M Quattromini; A Ranieri; G Raso; F Romano; F Ruggieri; G Selvaggi; L Silvestris; P Tempesta; G Zito; Y Gao; H Hu; D Huang; X Huang; J Lin; J Lou; C Qiao; T Wang; Y Xie; D Xu; R Xu; J Zhang; W Zhao; WB Atwood; LAT Bauerdick; F Bird; E Blucher; G Bonvicini; F Bossi; J Boudreau; TH Burnett; H Drevermann; RW Forty; C Grab; R Hagelberg; S Haywood; J Hilgart; E Jost; M Kasemann; J Knobloch; A Lacourt; E Lançon; I Lehraus; T Lohse; A Lusiani; M Martinez; P Mato; S Menary; T Meyer; A Minten; A Miotto; R Miquel; HG Moser; J Nash; P Palazzi; JA Perlas; F Ranjard; G Redlinger; L Rolandi; A Roth; J Rothberg; T Ruan; M Saich; D Schlatter; M Schmelling; W Tejessy; H Wachsmuth; W Wiedenmann; W Witzeling; J Wotschack; Z Ajaltouni; F Badaud; M Bardadin-Otwinowska; AM Bencheikh; R El Fellous; A Falvard; P Gay

Journal article

Evidence for b baryons in Z decays

D Decamp, B Deschizeaux, C Goy, JP Lees, MN Minard, R Alemany, F Ariztizabal, JM Crespo, M Delfino, E Fernandez, V Gaitan, L Garrido, LM Mir, A Pacheco, A Pascual, MG Catanesi, D Creanza, M de Palma, A Farilla, G Iaselli Show all

Physics Letters B | ELSEVIER SCIENCE BV | Published : 1992

DOI: 10.1016/0370-2693(92)90736-N

Abstract

In 160 000 hadronic Z decays recorded with the ALEPH detector at LEP, the yields of Λℓ- and Λℓ+ combinations have been measured. The observed excess of Λℓ- over Λℓ+ of 53±13 is interpreted as evidence for b baryons and their semileptonic decay. Assuming that three body decay processes such as Λb→Λc +ℓ -v dominate the semileptonic decay of b baryons, this ex cess corresponds to a product branching ratio BR(b→Λb)·BR(Λb→ Λc +ℓ-v)·BR(Λ c +→ΛX) = (0.95±0.22 (stat.)±0.21(syst.))%, where Λb and Λc + denote the bottom and charm baryons respectively. © 1992.