Author: Fernando Mart\'{\i}nez-Vidal (IFIC, Centro Mixto Universitat de Val\`encia-CSIC, Spain)
Title: Heavy quark production at the Z
Abstract: The most recent results on decays of \Zz~into final states including b- and c-quarks reported by the four LEP experiments and SLD at SLC are summarized. The average values of the decay rates of $\ztobb$ and $\ztocc$, $\Rb = 0.21661 \pm 0.00073$ and $\Rc = 0.1735 \pm 0.0044$ respectively, agree within one standard deviation with the Standard Model prediction. The rare decay $\ztobbbb$ is observed and its rate is found to be $\Rfourb = (5.4 \pm 2.3) \times 10^{-4}$. The upper limit on the flavor changing neutral current decay $\ztobq$, $\mathrm{q \neq b}$ is set to be $\Rfcnc < 2.4 \times 10^{-3}$ (90\% CL).
Comments: 9 pages, RevtexReport-no: Procceding DPF'99 ConferenceSubj-class: High Energy Physics - ExperimentSecondary Subject(s) from list:Journal-ref: Conference proceedings