A measurement of BB̄ mixing with the DELPHI detector at LEP

Abstract

The data collected during 1990 and 1991 LEP runs with the DELPHI detector have been analyzed to measure the probability χ for a B meson to undergo mixing before decay. A study based on events containing two identified leptons lying on opposite detector sides yielded χ=0.121±0.0400.044(stat.)±0.017(syst.); a comparison between the charge of a high pt muon and the one of the jet recoiling in the opposite direction gave χ=0.075±0.053 (stat. ⊕ syst.); the combined result is χ=0.101±0.035 (stat. ⊕ syst.). No signal of CP violation has been observed.The data collected during 1990 and 1991 LEP runs with the DELPHI detector have been analyzed to measure the probability χ for a B meson to undergo mixing before decay. A study based on events containing two identified leptons lying on opposite detector sides yielded χ=0.121±0.0400.044(stat.)±0.017(syst.); a comparison between the charge of a high pt muon and the one of the jet recoiling in the opposite direction gave χ=0.075±0.053 (stat. ⊕ syst.); the combined result is χ=0.101±0.035 (stat. ⊕ syst.). No signal of CP violation has been observed.