G. Alexander et al., A MEASUREMENT OF THE B-D(0) OSCILLATION FREQUENCY USING LEPTONS AND D-ASTERISK(+ -)-MESON/, Zeitschrift fur Physik. C, Particles and fields, 72(3), 1996, pp. 377-388
Data collected with the OPAL detector during 1990-1994 are used to mea
sure the time dependence of B-d(0) <----> <(B)over bar(d)(0)> mixing.
A sample of 348 D-+/- candidates with a lepton in the opposite hemisp
here are reconstructed, of which 167 +/- 25 are expected to be from B-
d(0) decays. The B-d(0) oscillation frequency is measured to be Delta
m(d) = 0.567 +/- 0.089(stat)(-0.023)(+0.029)(syst) ps(-1). A previousl
y published analysis of Delta m(d) using D-+/- and lepton candidates
in the same hemisphere and jet charge is also updated with a larger da
ta sample. From 1200 D(+/-)l(-/+) candidates, of which 778 +/- 84 are
expected to be from B-d(0) decays, we find a value of: Delta m(d) = 0
.539 +/- 0.060(stat) +/- 0.024(syst) ps(-1). The combined result of th
ese two analyses is Delta m(d) = 0.548 +/- 0.050(stat)(-0.019)(+0.023)
(syst) ps(-1).