The fourth family: a simple explanation for the observed pattern of   anomalies in B-CP asymmetries
  We show that a fourth family of quarks with $m_{t'}$ in the range of (400 - 600) GeV provides a rather simple explanation for the several indications of new physics that have been observed involving CP asymmetries of the b-quark. The built-in hierarchy of the 4$\times$4 mixing matrix is such that the $t'$ readily provides a needed {\it perturbation} ($\approx 15%$) to $\sin 2 \beta$ as measured in $B \to \psi K_s$ and simultaneously is the dominant source of CP asymmetry in $B_s \to \psi \phi$. The correlation between CP asymmetries in $B_s \to\psi \phi$ and $B_d\to\phi K_s$ suggests $m_{t'} \approx$ (400 - 600) GeV. Such heavy masses point to the tantalizing possibility that the 4th family plays an important role in the electroweak symmetry breaking. 
Amarjit Soni, Ashutosh Kumar Alok, Anjan Giri, Rukmani Mohanta and   Soumitra Nandi