using double-tag methods
The L3 Collaboration
M.Acciarri26 - et al.
26 INFN-Sezione di Milano, 20133 Milan, Italy
Received: 2 September 1999 / Published online: 3 February 2000 - © Springer-Verlag 2000
We present a combined measurement of and the semileptonic branching ratio of b quarks in Z decays, , using double-tag methods. Two analyses are performed on one million hadronic Z decays collected in 1994 and 1995. The first analysis exploits the capabilities of the silicon microvertex detector. The tagging of b-events is based on the large impact parameter of tracks from weakly decaying b-hadrons with respect to the e+ e- collision point. In the second analysis, a high-pt lepton tag is used to enhance the b-component in the sample and its momentum spectrum is used to constrain the model dependent uncertainties in the semileptonic b-decay. The analyses are combined in order to provide precise determinations of Rb and :
Copyright Società Italiana di Fisica, Springer-Verlag 2000