$b \to s$ Transitions in Family-dependent $U(1)^\prime$ Models

TL;DR

This paper investigates how family-dependent $U(1)'$ gauge symmetries can induce flavor-changing effects in $b o s$ transitions, analyzing constraints and potential explanations for observed anomalies in B-meson decays.

Contribution

It provides a systematic, model-independent framework for analyzing $b o s$ FCNC effects in family non-universal $U(1)'$ models, incorporating current experimental constraints.

Findings

Current anomalies in B-meson decays can be explained within this model class.

Constraints from $B_s$ mixing limit the parameter space of $U(1)'$ charges.

The framework can accommodate observed CP asymmetries.

Abstract

We analyze flavor-changing-neutral-current (FCNC) effects in the $b\to s$ transitions that are induced by family non-universal $U(1)'$ gauge symmetries. After systematically developing the necessary formalism, we present a correlated analysis for the $\Delta B =1, 2$ processes. We adopt a model-independent approach in which we only require family-universal charges for the first and second generations and small fermion mixing angles. We analyze the constraints on the resulting parameter space from $B_s - \bar B_s$ mixing and the time-dependent CP asymmetries of the penguin-dominated $B_d \to (\pi, \phi, \eta', \rho, \omega, f_0)K_S$ decays. Our results indicate that the currently observed discrepancies in some of these modes with respect to the Standard Model predictions can be consistently accommodated within this general class of models.