Author/Authors :
ALEPH Collaboration، نويسنده , , D. Buskulic، نويسنده , , D. Casper، نويسنده , , I. De Bonis، نويسنده , , D. Decamp، نويسنده , , P. Ghez، نويسنده , , C. Goy، نويسنده , , J.-P. Lees، نويسنده , , A. Lucotte، نويسنده , , M.-N. Minard، نويسنده , , P. Odier، نويسنده , , B. Pietrzyk، نويسنده , , F. Ariztizabal، نويسنده , , M. Chmeissani، نويسنده , , J.M. Crespo، نويسنده , , I. Efthymiopoulos، نويسنده , , E. Fernandez، نويسنده , , M. Fernandez-Bosman، نويسنده , , V. Gaitan، نويسنده , , Ll. Garrido، نويسنده , , et al.، نويسنده ,
Abstract :
A lower limit is set on the Bs0 meson oscillation parameter Δms using data collected from 1991 to 1994 by the ALEPH detector. Events with a high transverse momentum lepton and a reconstructed secondary vertex are used. The high transverse momentum leptons are produced mainly by b hadron decays, and the sign of the lepton indicates the particle/antiparticle final state in decays of neutral B mesons. The initial state is determined by a jet charge technique using both sides of the event. A maximum likelihood method is used to set a lower limit of Δms. The 95% confidence level lower limit on Δms ranges between 5.2 and 6.5(h̷c2) ps−1 when the fraction of b quarks from Z0 decays that form Bs0 messons is varied from 8% to 16%. Assuming that the B0s fraction is 12%, the lower limit would be Δms > 6.1(h̷c2) ps−1 at 95% confidence level. For xs = ΔmsτBs, this limit also gives xs > 8.8 using the B0s lifetime of τBs = 1.55 ± 0.11 ps and shifting the central value of τBs down by 1σ.
