P. Abreu et al., MEASUREMENT OF THE B-D(0) OSCILLATION FREQUENCY USING KAONS, LEPTONS AND JET CHARGE, Zeitschrift fur Physik. C, Particles and fields, 72(1), 1996, pp. 17-30
A measurement of the mass difference, Delta m(d), be tween the two phy
sical B-d(0) states has been obtained from the analysis of the impact
parameter distribution of a lepton emitted at large transverse momentu
m (p(t)) relative to the jet axis and from the analysis of the flight
distance distribution of secondary vertices tagged by either a high p(
t) lepton or an identified kaon. In the opposite hemisphere of the eve
nt, the charge of the initial quark has been evaluated using a high p(
t) lepton, a charged kaon or the mean jet charge, With 1.7 million had
ronic Z(0) decays recorded by DELPHI between 1991 and 1993, Delta m(d)
is found to be: Delta m(d) = 0.531 (+0.050)(-0.046) (stat.) +/- 0.078
(syst.) ps(-1).