A lower limit on the oscillation frequency of the 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 B-s(0) decays. Criteria designed to ensure precise proper time reconstruction select 277 D(s)(-)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 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(s) = 1.54(-0.13)(0.14) (stat) +/- 0.04 (syst) ps.
Study of the B-s(0)(B)over-bar(s)(0) oscillation frequency using D(s)(-)l(+) combinations in Z decays
SELVAGGI, Giovanna;DE PALMA, Mauro;NUZZO, Salvatore Vitale
1996-01-01
Abstract
A lower limit on the oscillation frequency of the 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 B-s(0) decays. Criteria designed to ensure precise proper time reconstruction select 277 D(s)(-)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 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(s) = 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.