Lifetimes of charged and neutral B hadrons using event topology

Collaboration
Apr, 1995
22 pages
Published in:
  • Z.Phys.C 68 (1995) 363-374
Report number:
  • CERN-PPE-95-059,
  • CERN-PPE-95-59
Experiments:

Citations per year

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Abstract: (Springer)
The lifetimes of charged and neutral B hadrons have been measured using data collected by the DELPHI experiment at LEP between 1991 and 1993. B hadrons are tagged as jets with a secondary vertex and the charge of the B candidate is taken to be the sum of the charges of the particles in the secondary vertex. Approximately 1,434,000 multihadronic Z0 decays yielded 1817 B hadron candidates. The B purity was estimated to be around 99.1±0.3%, and 83% (70%) of the events measured as neutral (charged) came from neutral (charged) B's. The mean lifetimes of charged and neutral B hadrons were found to be 1.72±0.08 (stat.) ±0.06 (syst.) ps and 1.58±0.11 (stat.)±0.09 (syst.) ps respectively. The ratio of their lifertimes, τcharged/τneutral, was 1.09−0.10+0.11 (stat.)±0.08 (syst.). By making assumptions about the Bs0 and Λb0 states, the B+ and B0 meson lifetimes were determined to be τB+ = 1.72 ± 0.08 (stat.) ±0.06 (syst.) ps and τB+ = 1.63 ± 0.14 (stat.)±0.13 (syst.) ps and the ratio of their lifetimes was:
  • electron positron: colliding beams
  • colliding beams: electron positron
  • electron positron: annihilation
  • annihilation: electron positron
  • Z0: electroproduction
  • electroproduction: Z0
  • Z0: nonleptonic decay
  • nonleptonic decay: Z0
  • bottom: pair production
  • pair production: bottom