## Research Papers in Physics and Astronomy

#### Date of this Version

7-14-2006

#### Abstract

We report results of a study of the *B*_{s}^{0} oscillation frequency using a large sample of *B*_{s}^{0} semileptonic decays corresponding to approximately 1 fb^{-1} of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron Collider in 2002–2006. The amplitude method gives a lower limit on the *B*_{s}^{0} oscillation frequency at 14.8 ps^{-1} at the 95% C.L. At Δ*m*_{s} = 19 ps^{-1}, the amplitude deviates from the hypothesis *A*= 0 (1) by 2.5 (1.6) standard deviations, corresponding to a two-sided C.L. of 1% (10%). A likelihood scan over the oscillation frequency, Δ*m*_{s}, gives a most probable value of 19 ps^{-1} and a range of 17 < Δ*m*_{s} < 21 ps^{-1} at the 90% C.L., assuming Gaussian uncertainties. This is the first direct two-sided bound measured by a single experiment. If Δ*m*_{s} lies above 22 ps^{-1}, then the probability that it would produce a likelihood minimum similar to the one observed in the interval 16–22 ps^{-1} is (5.0 ± 0.3)%.

## Comments

Published by American Physical Society.

Phys. Rev. Lett.97, 021802 (2006). http://prl.aps.org. Copyright © 2006 American Physical Society. Permission to use.