Study of Bs0 oscillations and lifetime using fully reconstructed Ds decays

A search for oscillations is performed using approximately 4 million events collected by the ALEPH experiment during 1991–1995. candidates are partially reconstructed by combining tracks with fully reconstructed candidates. The production flavour is estimated from the sign of the opposite hemisphere charge, a fragmentation kaon in the same hemisphere, or a lepton in the opposite hemisphere. From a total sample of 1620 candidates, with a purity estimated to be 22%, all values of below 3.9 ps and between 6.5 and 8.8 ps are excluded at 95% CL. From the same sample, the lifetime is measured to be ps. This analysis selects mainly hadronic decays and is statistically independent of a previous ALEPH analysis selecting candidates. Combining these two analyses yields ps at 95% CL and ps.