EPJ

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EPJ C - Particles and Fields
Particles and Fields
Eur. Phys. J. C 1, 439-459

Measurement of $\vec{{\bf f}(\vec{c} \to{\rm D}^{*+} X)}$, $\vec{{\bf f}({\rm b} \to {\rm D}^{*+} X)}$ and $\vec{\Gamma_{{\rm c\bar c}}/\Gamma_{\rm had}}$ using ${\rm D}^{*\pm}$mesons

The OPAL Collaboration, K. Ackerstaff 8 et al.

8 CERN, European Organisation for Particle Physics, CH-1211 Geneva 23, Switzerland

Received: 18 July 1997

Abstract
The production rates of ${\rm D}^{*\pm}$ mesons in charm and bottom events at centre-of-mass energies of about $91~\ GeV$and the partial width of primary ${\rm c}\overline{{\rm c}}$ pairs in hadronic ${\rm Z}^0$ decays have been measured at LEP using almost 4.4 million hadronic ${\rm Z}^0$ decays collected with the OPAL detector between 1990 and 1995. Using a combination of several charm quark tagging methods based on fully and partially reconstructed ${\rm D}^{*\pm}$ mesons, and a bottom tag based on identified muons and electrons, the hadronisation fractions of charm and bottom quarks into ${\rm D}^{*\pm}$ mesons have been found to be ${{\rm f}\,({\rm b}\to{{\rm D}^{*{\scriptscriptstyle +}}} X)} = 0.173\pm 0.016\pm 0.012$ and
${{\rm f}\,({\rm c}\to {{\rm D}^{*{\scriptscriptstyle +}}} X)} = 0.222\pm 0.014\pm 0.014\ .$
The fraction of ${\rm c}\overline{{\rm c}}$ events in hadronic ${\rm Z}^0$ decays, $\Gamma_{\!\smash{{\rm c}\overline{{\rm c}}}\mathstrut}/\Gamma_{\!\smash{{\rm ha... ...\Gamma({\rm Z}^0\to{\rm c}\overline{{\rm c}}) / \Gamma({\rm Z}^0\to\rm hadrons)$,is determined to be

\begin{displaymath} \Gamma_{\!\smash{{\rm c}\overline{{\rm c}}}\mathstrut}/\Gamm... ...mash{{\rm had}}\mathstrut}= 0.180\pm 0.011\pm 0.012\pm 0.006\ .\end{displaymath}

In all cases the first error is statistical, and the second one systematic. The last error quoted for $\Gamma_{\!\smash{{\rm c}\overline{{\rm c}}}\mathstrut}/\Gamma_{\!\smash{{\rm had}}\mathstrut}$ is due to external branching ratios.

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