Author: Thomas R. Junk (Carleton University, Ottawa, Canada)
Title: Recent Heavy-Flavor Measurements from OPAL
Abstract: A selection of recent heavy-flavor results from OPAL using the LEP1 data sample are presented. The average polarization of b baryons in hadronic Z^0 decay has been measured to be -0.56^{+0.20}_{-0.13} (stat.) +- 0.09(syst.) using semileptonic decays of Lambda_b baryons. A search has been conducted for the radially excited D*' and has produced a 95\% CL upper limit on its production off(Z^0 -> D*'+-(2629))xBr(D*'+- -> D*+- pi+ pi-) < 2.1x10^{-3}.Finally, the measurement of the product branching ratio$f(b -> Lambda_b)xBr(Lambda_b -> Lambda X)= (2.67 +- 0.38 (stat)^{+0.67}_{-0.60}(syst.))% has been made. This measurement, along with an earlier measurement of the product branching ratiof(b -> Lambda_b)xBr(Lambda_b -> Lambda l X), has been used to compute an updatedR_{Lambda l} = Br(Lambda_b -> Lambda l X)/Br(Lambda_b -> \Lambda X)=(8.0 +- 1.2 (stat.) +- 0.9 (syst.))%, consistent with the expected lowsemileptonic branching fraction of the Lambda_b inferredfrom its short lifetime compared to the other b hadrons.
Comments: 9 Pages, LaTeX. Proceedings contributed to DPF'99, UCLA,Parallel session talk 3.02.Report-no: