Measurement of the semileptonic b branching fractions and average b mixing parameter in Z decays

Abstract

The semileptonic branching fractions for primary and cascade b decays BR(b -> lepton-), BR(b -> c -> lepton+) and BR(b -> cbar -> lepton-) were measured in hadronic Z decays collected by the DELPHI experiment at LEP. The sample was enriched in b decays using the lifetime information and various techniques were used to separate leptons from direct or cascade b decays. By fitting the momentum spectra of di-leptons in opposite jets, the average b mixing parameter chi-bar was also extracted. The following results have been obtained: BR(b -> lepton-) = (10.70 +/- 0.08 (stat) +/- 0.21 (syst)_{+0.44}^{-0.30}(model))% BR(b -> c -> lepton+) = (7.98 +/- 0.22 (stat) +/- 0.21 (syst)^{+0.14}_{-0.20}(model))% BR(b -> cbar -> lepton-) = (1.61 +/- 0.20 (stat) +/- 0.17 (syst)^{+0.30}_{-0.44}(model))% chi-bar = 0.127 +/- 0.013 (stat) +/- 0.005 (syst) +/- 0.004(model)

arXiv comment43 pages, 7 figures, Accepted by Eur. Phys. J. C

Cited by in corpus (7)

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• Measurement of Ratios of Fragmentation Fractions for Bottom Hadrons in p-pbar Collisions at sqrt{s}=1.96 TeV
• Measurement of the Branching Fraction for Inclusive Semileptonic B Meson Decays
• Measurement of the top-quark mass using a leptonic invariant mass in $pp$ collisions at $\sqrt{s}=13\text{TeV}$ with the ATLAS detector
• Inclusive semileptonic branching ratios of b hadrons produced in Z decays
• Measurement of the Forward-Backward Asymmetries of e+e- -> Z -> b bbar and e+e- -> Z -> c cbar using prompt leptons
• Search for B0_s - anti-B0_s oscillations in DELPHI using high-p_t leptons