Limit on $B^0 s$ oscillation using a jet charge methodReportar como inadecuado

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1 LAPP - Laboratoire d-Annecy-le-Vieux de Physique des Particules 2 LPC - Laboratoire de Physique Corpusculaire - Clermont-Ferrand 3 LLR - Laboratoire Leprince-Ringuet 4 CPPM - Centre de Physique des Particules de Marseille 5 LAL - Laboratoire de l-Accélérateur Linéaire

Abstract : A lower limit is set on the B {s}^{0} meson oscillation parameter \Delta m {s} 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 \, \Delta m {s}. The 95\% confidence level lower limit on \Delta m s ranges between 5.2 and 6.5\hbar-c^{2}~ps^{-1} when the fraction of b quarks from Z^0 decays that form B {s}^{0} mesons is varied from 8\% to 16\%. Assuming that the B {s}^{0} fraction is 12\%, the lower limit would be \Delta m {s} 6.1\hbar-c^{2}~ps^{-1} at 95\% confidence level. For x s = \Delta m s \, \tau {B s}, this limit also gives x s 8.8 using the B {s}^{0} lifetime of \tau {B s} = 1.55 \pm 0.11~ps and shifting the central value of \tau {B s} down by 1\sigma.

Autor: D. Buskulic - D. Casper - I. De Bonis - D. Decamp - P. Ghez - C. Goy - J.P. Lees - A. Lucotte - M.N. Minard - P. Odier - B. Pietr



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