Observation of the semileptonic decays of BS and Λb hadrons at LEP

D Buskulic; D Decamp; C Goy; JP Lees; MN Minard; B Mours; R Alemany; F Ariztizabal; P Comas; JM Crespo; M Delfino; E Fernandez; V Gaitan; L Garrido; A Pacheco; A Pascual; 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; E Blucher; G Bonvicini; F Bossi; J Boudreau; TH Burnett; H Drevermann; RW Forty; R Hagelberg; J Harvey; S Haywood; J Hilgart; R Jacobsen; B Jost; J Knobloch; E Lançon; I Lehraus; T Lohse; A Lusiani; M Martinez; P Mato; T Mattison; H Meinhard; S Menary; T Meyer; A Minten; 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; F Sefkow; W Tejessy; H Wachsmuth; W Wiedenmann; T Wildish; W Witzeling; J Wotschack; Z Ajaltouni; F Badaud; M Bardadin-Otwinowska; AM Bencheikh; R El Fellous; A Falvard

Journal article

Observation of the semileptonic decays of BS and Λb hadrons at LEP

D Buskulic, D Decamp, C Goy, JP Lees, MN Minard, B Mours, R Alemany, F Ariztizabal, P Comas, JM Crespo, M Delfino, E Fernandez, V Gaitan, L Garrido, A Pacheco, A Pascual, 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)91654-R

Abstract

In 450 000 hadronic Z decays recorded with the ALEPH detector at LEP, the yields of Ds -ℓ+ and Λc +ℓ- combinations have been measured. 16.0 ± 4.3 Ds -ℓ+ combinations were observed in the Ds - → ππ- channel and 17.0 ± 4.5 combinations were observed in the Ds - → K*0K- channel. 21.0 ± 5.0 Λc +ℓ- combinations were observed, with the Λc + reconstructed in the decay mode Λc + → pK-π+. These events provide evidence for the decays Bs → Ds -Xℓ+ν and Λb → Λc +Xℓ-ν. Assuming that the Bs and Λb semileptonic decays are dominantly three-body, these observed yields, after background subtraction, translate into the following product branching ratios: Br(b → Bs)Br(Bs → Ds -Xℓ+ν) = 0.040±0.011 -0.012 +0.010,..

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