B_s^0-\bar{B}_s^0 mixing and B -> \pi K decays in stringy leptophobic Z^\prime

TL;DR

This paper explores how a string-inspired leptophobic Z' boson can influence B_s mixing and B -> pi K decays, potentially explaining observed CP asymmetry anomalies within constrained parameter space.

Contribution

It demonstrates that a leptophobic Z' from string theory can account for B decay anomalies while satisfying flavor constraints, a novel connection between string models and flavor physics.

Findings

Large deviations in B -> pi K CP asymmetries are possible within constraints.

Allowed Z' mass and couplings are tightly constrained by B_s mixing and B -> pi K branching ratios.

The model can accommodate puzzling experimental data in B decay CP asymmetries.

Abstract

We consider a leptophobic Z^\prime scenario in a flipped SU(5) grand unified theory obtained from heterotic string theory. We show that the allowed Z^\prime mass, flavor conserving and flavor changing couplings of the Z^\prime to the down-type quarks are strongly constrained by the mass difference in B_s-\bar{B}_s system and the four branching ratios of B -> \pi K decays. It is shown that even under these constraints large deviations in direct and/or indirect CP asymmetries of B \to \pi K decays from the SM expectations are allowed. Especially it is possible to accommodate the apparent puzzling data in B -> \pi K CP asymmetries.