2018 Impact factor 4.843
Particles and Fields

Eur. Phys. J. C 10, 415-442
DOI 10.1007/s100529900121

A precise measurement of the partial decay
width ratio ${R_{\mathrm{b}}}^0 = \Gamma_{\mathrm{b\bar{b}}}/\Gamma_{\mathrm{had}}$

The DELPHI Collaboration

P.Abreu21 - et al.

21 LIP, IST, FCUL - Av. Elias Garcia, 14-1o, PT-1000 Lisboa Codex, Portugal  

Received: 18 December 1998 / Revised version: 26 April 1999 / Published online: 3 August 1999

The partial decay width of the Z to ${\mathrm b\bar{\mathrm b}}$ quark pairs has been measured by the DELPHI detector at LEP using data taken in the years 1992 to 1995. Decays of b-hadrons were tagged by several methods using tracks with large impact parameters and/or reconstructed secondary vertices, complemented by event shape variables. Combining these methods in a multivariate analysis the value

\frac{\Gamma({\mathrm Z \rightarrow {\mathrm b\bar{\mathrm b...
 ...34 \pm 0.00067({\mathrm {stat}}) \pm 0.00060 ({\mathrm {syst}})\end{displaymath}

was obtained, where the ${\mathrm c} \bar {\mathrm c}$ production fraction was fixed to its Standard Model value.

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