From a data sample of 450 000 hadronic events recorded with the ALEPH detector at LEP, 92 +/- 10 events are observed containing a J/psi meson decaying to mu+mu- or e+e-. From these data the measured inclusive branching fraction for a b flavoured hadron to decay to a J/psi is BR(b --> J/psiX) = (1.21 +/- 0.13 (stat.) +/- 0.08 (syst.))%, and the average b hadron lifetime in the events tagged with a J/psi is tau(b) = 1.35(-0.17)+0.19 +/- 0.05 ps. Five events are observed consistent with the exclusive decay B+/- --> J/psiK+/- and from these events the exclusive branching fraction is measured to be BR(B+/- --> J/psiK+/-) = (0.22 +/- 0.10 +/- 0.02)%. Upper limits for other exclusive branching ratios are given.
MEASUREMENTS OF MEAN LIFETIME AND BRANCHING FRACTIONS OF B HADRONS DECAYING TO J/PSI
LUSIANI, Alberto;ROLANDI, LUIGI;LIGABUE, FRANCO;
1992
Abstract
From a data sample of 450 000 hadronic events recorded with the ALEPH detector at LEP, 92 +/- 10 events are observed containing a J/psi meson decaying to mu+mu- or e+e-. From these data the measured inclusive branching fraction for a b flavoured hadron to decay to a J/psi is BR(b --> J/psiX) = (1.21 +/- 0.13 (stat.) +/- 0.08 (syst.))%, and the average b hadron lifetime in the events tagged with a J/psi is tau(b) = 1.35(-0.17)+0.19 +/- 0.05 ps. Five events are observed consistent with the exclusive decay B+/- --> J/psiK+/- and from these events the exclusive branching fraction is measured to be BR(B+/- --> J/psiK+/-) = (0.22 +/- 0.10 +/- 0.02)%. Upper limits for other exclusive branching ratios are given.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
