Measurement of the Charge Asymmetry in Semileptonic B_s⁰ Decays

Authors

V. M. Abazov, Joint Institute for Nuclear Research, Dubna, Russia
Kenneth A. Bloom, University of Nebraska-LincolnFollow
Gregory R. Snow, University of Nebraska-LincolnFollow
D0 Collboration

Date of this Version

4-13-2007

Comments

Published by Am Physical Soc. PRL 98, 151801 (2007). Copyright 2007. Permission to use. http://prl.aps.org

Abstract

We have performed the first direct measurement of the time-integrated flavor untagged charge asymmetry in semileptonic B_s⁰ decays A_SL^s,unit by comparing the decay rate of B_s⁰ →μ⁺D_s^- νX, where D_s^-→ φ π^- and φ → K⁺K^-, with the charge-conjugate B̅_s⁰ decay rate. This sample was selected from 1.3 fb^-1 of data collected by the D0 experiment in run II of the Fermilab Tevatron collider. We obtain A_SL^s,unit= [1.23 ± 0.97(stat) ± 0.17(syst)] x 10^-2. Assuming that Δm_s/Γ̅_s >> 1, this result can be translated into a measurement of the CP-violating phase in B_s⁰ mixing: ΔΓ_s/ Δm_stanφ_s = [2.45 ± 1.93(stat) ± 0.35(syst)] x 10^-2.