{First observation of the decay $B_s^0\to D_s^{-}{D}_s^{+}$ and measurement of its branching ratio}

We report the observation of the exclusive decay Bs0-->Ds-Ds+ at the 7.5 standard deviation level using 355 pb-1 of data collected by the CDF II detector in $p\overline{p}$ collisions at $\sqrt{s}=1.96$ TeV at the Fermilab Tevatron. We measure the relative branching ratio [script B](Bs0-->Ds-Ds+)/[script B](B0-->D-Ds+) =1.44-0.44+0.48. Using the world average value for [script B](B0-->D-Ds+), we find [script B](Bs0-->Ds-Ds+) =(9.4-4.2+4.4)×10-3. This provides a lower bound DeltaGammasCP/Gammas> =2[script B](Bs0-->Ds-Ds+)>1.2×10-2 at 95% C.L.

Duke Scholars

Author Alfred T. Goshaw Physics

Author Ashutosh V. Kotwal Physics

Author Mark C. Kruse Physics

Author Seog Oh Physics