Measurement of Polarization and Search for CP-Violation in $B_s^0 \to   \phi\phi$ Decays
  We present the first measurement of polarization and CP-violating asymmetries in $B_s^0$ decays into two light vector mesons, $B_s^0 \to \phi\phi$, and an improved determination of its branching ratio using 295 decays reconstructed in a data sample corresponding to 2.9 fb^-1 of integrated luminosity collected by the CDF experiment at the Fermilab Tevatron collider. The fraction of longitudinal polarization is determined to be $\fL = 0.348 \pm 0.041 ({\rm stat}) \pm 0.021 ({\rm syst})$, and the branching ratio $BR ($B_s^0 \to \phi\phi$) = [2.32 \pm 0.18 ({\rm stat}) \pm 0.82 ({\rm syst})] \times 10^{-5}$. Asymmetries of decay angle distributions sensitive to \CP\ violation are measured to be $ A_u = - 0.007 \pm 0.064 \stat \pm 0.018 \syst$ and $ A_v = -0.120 \pm 0.064 \ stat \pm 0.016\syst$. 
CDF Collaboration
hep-ex hep-ph