Search for CP violation in $B_s^0 \to \mu^+ D_s^- X$ decays in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV

We have performed a search for CP violation in a sample of Bs0→μ+Ds-X decays corresponding to 5 fb-1 of proton-antiproton collisions collected by the D0 detector in Run II at the Fermilab Tevatron Collider. New physics in Bs0 mixing could contribute a significant CP violating weak phase, which would be observed as a difference in the decay-time distribution for Bs0→B s0 oscillated states versus that for B s0→Bs0. A fit to the decay-time distributions of the Bs0/B s0 candidates yields the flavor-specific asymmetry afss=[-1.7±9.1(stat)-1.5+1.4(syst)]×10-3, which excludes CP violation due to new physics within the experimental sensitivity.