Study of oscillations and lifetime using fully reconstructed decays
The ALEPH Collaboration
R.Barate et al.
Laboratoire de Physique des Particules (LAPP), IN2P3-CNRS, F-74019 Annecy-le-Vieux Cedex, France
Received: 12 December 1997 / Revised version: 24 February 1998 / Published online: 23 June 1998
A search for oscillations is performed using approximately 4 million events collected by the ALEPH experim ent 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-1 and between 6.5 and 8.8 ps-1 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-1at 95%CL and ps.