Probing new physics in B -> phi pi decay

Abstract

We analyze the rare decay mode $B \to \phi \pi $, which is a pure penguin induced process, receiving dominant contribution from the electroweak penguins. Thus the standard model branching ratio is expected to be very small, which makes it as a sensitive probe of new physics. Using QCD factorization approach, we find the branching ratio in the standard model as $Br(B^- \to \phi \pi^-)\simeq 5 \times 10^{-9}$. Exploring some of the beyond standard model scenarios the branching ratio is found to be $\sim {\cal O}(10^{-8})$ in the minimal supersymmetric standard model (MSSM) with mass insertion approximation and in the extended technicolor model (TC2). The existence of an extra vector-like down quark (VLDQ) model predicts it to be $\sim {\cal O}(10^{-7})$. The recent BaBar result on $B^0 \to \phi \pi^0$ might be a strong indication of new physics effect present in the penguin induced process $B \to \phi \pi$.