Probing New Physics in $B_s$ and $D$ mixings, and $A_{\rm CP}(B^+ \to   J/\psi K^+)$
  A 4th generation could be consistent with the recently measured $\Delta m_{B_s}$ as well as ${\cal B}(b\to s\ell^+\ell^-)$, which are SM-like, but generate large $\sin2\Phi_{B_s} \simeq -0.5$ to -0.7. The sign is determined by the hint for New Physics in CPV measurements in charmless B decays. The $4\times 4$ unitarity allows one to connect to all processes involving flavor. Fixing $V_{t'b}$, $V_{t's}$ and $V_{t'd}$ by $Z\to b\bar b$, $b\to s$ and $s\to d$ processes, we predict $D$ mixing to be close to the current bound. As a further corollary, we suggest that $A_{\rm CP}(B^+ \to J/\psi K^+)$ could be at 1% level or higher, where we give plausibility of an associated strong phase. Our predictions can be tested in the near future. 
George W.S. Hou