A lower limit on the oscillation frequency of the B(s)0-anti-B(s)0 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 Ds- candidates reconstructed in seven different decay modes as evidence of semileptonic B(s)0 decays. Criteria designed to ensure precise proper time reconstruction select 277 Ds-l+ combinations. The initial state of these B(s)0 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 B(s)0-anti-B(s)0 oscillation frequency is Delta m(s) > 6.6 ps(-1). The same data is used to update the measurement of the B(s)0 lifetime, tau(B(s)0) = 1.54 (-0.13)(+0.14) (stat) +/- 0.04 (syst) ps.
Study of the B(s)0 anti-B(s)0 oscillation frequency using D(s)- l+ combinations in Z decays
G. Batignani;CIOCCI, MARIA AGNESE;FERRANTE, ISIDORO;MESSINEO, ALBERTO MARIA;TONELLI, GUIDO EMILIO;
1996-01-01
Abstract
A lower limit on the oscillation frequency of the B(s)0-anti-B(s)0 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 Ds- candidates reconstructed in seven different decay modes as evidence of semileptonic B(s)0 decays. Criteria designed to ensure precise proper time reconstruction select 277 Ds-l+ combinations. The initial state of these B(s)0 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 B(s)0-anti-B(s)0 oscillation frequency is Delta m(s) > 6.6 ps(-1). The same data is used to update the measurement of the B(s)0 lifetime, tau(B(s)0) = 1.54 (-0.13)(+0.14) (stat) +/- 0.04 (syst) ps.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.