Measurement of the partial width of the Z0 into b anti-b final states using their semileptonic decays

Collaboration
May, 1992
33 pages
Published in:
  • Z.Phys.C 56 (1992) 47-62
Report number:
  • CERN-PPE-92-079,
  • CERN-PPE-92-79
Experiments:

Citations per year

19921993199419951996051015202530
Abstract: (Springer)
The spectra of prompt electrons and muons from the semi-leptonic decays of heavy hadrons produced inZ0 decays have been used to measure the coupling of theZ0 tob quarks weighted by theB hadrons mean semi-leptonic branching fraction, giving a value:BR_{sl}^b *{{\Gamma _{b\bar b} } \mathord{\left/ {\vphantom {{\Gamma _{b\bar b} } {\Gamma _H }}} \right. \kern-\nulldelimiterspace} {\Gamma _H }} = 0.0221 \pm 0.0015. The data has also been used to measure the value of the fragmentation parameter, defined in the context of the LUND PS Model, version 7.2, giving:\varepsilon (b) = \left( {8\begin{array}{*{20}c}{ + 5}\\{ - 3}\\ \end{array}\pm 2} \right)10^{ - 3} . The corresponding value of the mean fraction of the beam energy taken by aB hadron in the fragmentation of ab quark is:\overline {X_E^b }= 0.69\begin{array}{*{20}c}{ + 0.02}\\{ - 0.03}\\ \end{array}\pm 0.01. If the values ofΓbbˉ\Gamma _{b\bar b} andΓH are taken from the Standard Model, the following value is obtained for the mean semi-leptonic braching fraction ofB hadrons: BRslb=(10.1±0.7)%. Taking the value of{{\Gamma _{b\bar b} } \mathord{\left/ {\vphantom {{\Gamma _{b\bar b} } {\Gamma _{\rm H} }}} \right. \kern-\nulldelimiterspace} {\Gamma _{\rm H} }} from an independent analysis of DELPHI data based on the use of the boosted sphericity product, a value: BRslb=(10.1±1.3)% is obtained.
  • electron positron: colliding beams
  • colliding beams: electron positron
  • electron positron: annihilation
  • annihilation: electron positron
  • Z0: electroproduction
  • electroproduction: Z0
  • Z0: nonleptonic decay
  • nonleptonic decay: Z0
  • Z0: width
  • bottom: pair production