Explaining B \to K pi anomaly with non-universal Z' boson

Abstract

We study the effect of non-universal $Z^{\prime }$ boson in the decay modes $B\to K\pi$. In the standard model these modes receive dominant contributions from $b\to s$ QCD penguins. Therefore, in this limit one expects $S_{{\pi }^0{K}^0}\approx \sin 2\beta$, $A_{{\pi }^0{K}^0}\approx 0$ and $A_{{\pi }^0{K}^{-}}\approx A_{{\pi }^{+}{K}^{-}}$. The corrections due to the presence of small non-penguin contributions is found to yield $S_{{\pi }^0{K}^0}>\sin 2\beta$ and $\Delta A_{CP}(K\pi )\simeq 2.5$. However, the measured value of $S_{{\pi }^0{K}^0}$ is less than $\sin 2\beta$ and $\Delta A_{CP}(K\pi )\simeq 15$. We show the model with a non-universal $Z^{\prime }$ boson can successfully explain these anomalies.

Comments: 11 pages, 3 figures