  After a brief review of B_s^0 - \bar B_s^0 oscillations, we discuss the weak
decays B_s^0 -> J/\psi\phi and B_s^0 -> J/\psi f_0(980) and the ratio
R_{f_0/\phi} of their decay rates in the light of recent measurements by the
LHCb, D0 and CDF Collaborations. We point out that the experimental values for
R_{f_0/\phi} impose tight limits on new physics contributions to both decay
channels.
