| Abstract: |
Using the full Upsilon(5S) data sample from the Belle experiment, we present measurements of the branching fractions:
B(Bs -> Ds Dsbar ) = (0.58+-0.10+-0.13)%,
B(Bs -> Ds*Dsbar ) = (1.8 +-0.2 +-0.4 )%, and
B(Bs -> Ds*Dsbar*) = (2.0 +-0.3 +-0.5 )%; the sum is
B(Bs -> Ds(*)Ds(*))=(4.3 +-0.4 +-1.0)%.
Assuming Bs -> Ds(*)Ds(*) saturates decays to CP-even final states, the branching fraction constrains the ratio DeltaGamma_s/cos(phi_s), where DeltaGamma_s is the difference in widths between the two Bs-Bsbar mass eigenstates, and phi_s is the CP-violating phase in Bs-Bsbar mixing.
Assuming phi_s=0, our result implies DeltaGamma_s = 0.090+-0.009+-0.022
We discuss the uncertainties in the relation between DeltaGamma_s and the branching fraction of Bs -> Ds(*)Ds(*) and other methods to measure DeltaGamma_s. We also report the longitudinal polarization fraction of
Bs -> Ds*Ds* to be 0.11 +0.30-0.28 +0.04-0.05. |
