par Abdallah, Jalal Mohamad J.;Alderweireld, Thomas;Bertrand, Daniel 
;D'Hondt, Jorgen;De Clercq, Catherine;Lemonne, Jacques ;Van Lysebetten, Ann;Van Remortel, Nick;Wickens, John H. ; [et al.]
Référence Physics letters. Section B, 585, 1-2, page (63-84)
Publication Publié, 2004-04
;D'Hondt, Jorgen;De Clercq, Catherine;Lemonne, Jacques ;Van Lysebetten, Ann;Van Remortel, Nick;Wickens, John H. ; [et al.]Référence Physics letters. Section B, 585, 1-2, page (63-84)
Publication Publié, 2004-04
Article révisé par les pairs
| Résumé : | The form factor of Λb 0 baryons is estimated using 3.46×106 hadronic Z decays collected by the DELPHI experiment between 1992 and 1995. Charmed Λc + baryons fully reconstructed in the pK-π+, pK S 0, and Λπ+π+π - modes, are associated to a lepton with opposite charge in order to select Λb 0→Λc +l-ν̄l decays. From a combined likelihood and event rate fit to the distribution of the Isgur-Wise variable w, and using the Heavy Quark Effective Theory (HQET), the slope of the b-baryon form factor is measured to be ρ̂2=2.03±0.46(stat) -1.00 +0.72(syst). The exclusive semileptonic branching fraction Br(Λb 0→Λc +l-ν̄l) can be derived from ρ̂2 and is found to be (5.0-0.8 +1.1(stat)-1.2 +1.6(syst))%. Limits on other branching fractions are also obtained. © 2004 Published by Elsevier B.V. |
