The fourth family: a simple explanation for the observed pattern of anomalies in B-CP asymmetries

Abstract

We show that a fourth family of quarks with $m_{t^{\prime }}$ 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 $t^{\prime }$ 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 $B_s\to \psi \varphi$. The correlation between CP asymmetries in $B_s\to \psi \varphi$ and $B_d\to \varphi K_s$ suggests $m_{t^{\prime }}\approx$ (400 - 600) GeV. Such heavy masses point to the tantalizing possibility that the 4th family plays an important role in the electroweak symmetry breaking.

Comments: 6 pages, 2 figures; v4: Updated version to appear in Phys LettB; minor changes (including the title) & few refs. added