A lower limit on the oscillation frequency of the B0sB0s system is obtained from approximately four million hadronic Z decays accumulated using the ALEPH detector at LEP from 1991 to 1995. Leptons are combined with opposite sign D-s candidates reconstructed in seven different decay modes as evidence of semileptonic B0s decays. Criteria designed to ensure precise proper time reconstruction select 277 D-s l+ combinations. The initial state of these B0s candidates is determined using an algorithm optimized to efficiently utilise the tagging information available for each event. The limit at 95% confidence level on the B0sB0s oscillation frequency is Δms > 6.6 ps-1. The same data is used to update the measurement of the B0s lifetime, τs = 1.54 +0.14-0.13 (stat) +/- 0.04 (syst) ps.
Study of the Bs0s0 oscillation frequency using Ds− ℓ+ combinations in Z decays
GREGORIO, ANNA;BOSISIO, LUCIANO;GIANNINI, GIANROSSANO;
1996-01-01
Abstract
A lower limit on the oscillation frequency of the B0sB0s system is obtained from approximately four million hadronic Z decays accumulated using the ALEPH detector at LEP from 1991 to 1995. Leptons are combined with opposite sign D-s candidates reconstructed in seven different decay modes as evidence of semileptonic B0s decays. Criteria designed to ensure precise proper time reconstruction select 277 D-s l+ combinations. The initial state of these B0s candidates is determined using an algorithm optimized to efficiently utilise the tagging information available for each event. The limit at 95% confidence level on the B0sB0s oscillation frequency is Δms > 6.6 ps-1. The same data is used to update the measurement of the B0s lifetime, τs = 1.54 +0.14-0.13 (stat) +/- 0.04 (syst) ps.Pubblicazioni consigliate
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