Measurement of the oscillation frequency
The L3 Collaboration
M.Acciarri27 - et al.
27 INFN-Sezione di Milano, I-20133 Milan, Italy
Received: 20 February 1998 / Revised version: 23 March 1998 / Published online: 12 August 1998
Time-dependent mixing is studied using about two million hadronic Z decays registered by L3 in 1994 and 1995. For this study three techniques are used. Tagging of the b-quark charge at decay time is performed by identifying leptons from semileptonic B decays. The flavour of the b quark at production time is determined from the charge of the lepton in the opposite hemisphere or by using a jet-charge technique. The proper time of the B-particle decay is obtained by reconstructing the production and decay vertices or by a measurement of the lepton impact parameter. The combined result for the frequency of meson oscillations is