Testing the Non-universal Z^\prime Model in Bs -> \phi \pi^0 Decay

TL;DR

This paper investigates how a non-universal Z' boson could significantly alter the branching ratio and CP asymmetry of the B_s -> phi pi^0 decay, providing potential signals for new physics beyond the Standard Model.

Contribution

It presents a detailed analysis of the effects of a non-universal Z' boson on B_s -> phi pi^0 decay within the QCD factorization framework, highlighting possible deviations from the Standard Model predictions.

Findings

Branching ratio can vary by a factor of three due to Z' effects.

CP asymmetry could reach up to 55% with Z' influence.

Potential to use decay measurements to constrain Z' boson properties.

Abstract

The branching ratio and direct CP asymmetry of the decay mode $B_s \to \phi \pi^0$ have been calculated within the QCD factorization approach in both the standard model (SM) and the non-universal $Z^\prime$ model. In the standard model, the CP averaged branching ratio is about $1.3\times 10^{-7}$. Considering the effect of $Z^\prime$ boson, we found the branching ratio can be enlarged three times or decreased to one third %by the effect of $Z^\prime$ boson within the allowed parameter spaces. Furthermore, the direct CP asymmetry could reach 55% with a light $Z^\prime$ boson and suitable CKM phase, compared to 25% predicted in the SM. The enhancement of both branching ratio and CP asymmetry cannot be realized at the same parameter spaces, thus, if this decay mode is measured in the upcoming LHC-b experiment and/or Super B-factories, the peculiar deviation from the SM may provide a signal of the non-universal $Z^\prime$ model, which can be used to constrain the mass of $Z^\prime$ boson in turn.