Study of the decay B_s⁰→D_s(^*) D_s(^*)

Abstract

We report a study of the decay B_s⁰→D_s(^*) D_s(^*)using a data sample corresponding to 1.3 fb^-1 of integrated luminosity collected by the D0 experiment in 2002-2006 during run II of the Fermilab Tevatron collider. One D_s(^*) meson was partially reconstructed in the decay D_s→ø μ ν, and the other D_s(^*) meson was identified using the decay D_s→ ø π where no attempt was made to distinguish D_s and D_s^* states. For the branching fraction Br(B_s⁰→D_s(^*)D_s(^*)) we obtain a 90% C.L. range [0.002,0.080] and central value 0.039_-0.017^+0.019(stat)_-0.015^+0.016(syst). This was subsequently used to make the most precise estimate of the width difference Δ Γ_s^CP in the B_s⁰-B‾_s ⁰ system: ΔΓ_s^CP/Γ_s=0.079 _-0.035^+0.038(stat)_-0.030^+0.031(syst).