An explicit Z ′-boson explanation of the B → K ∗ μ + μ − anomaly

A global fit to the recent B → K ∗ μ + μ − data shows indications for a large new-physics contribution to the Wilson coefficient of the semi-leptonic vector operator. In this article we consider a simple Z ′-boson model of 3-3-1 type that can accommodate such an effect without violating any other constraint from quark-flavour physics. Implications for yet unobserved decay modes such as B → X s ν v̄ and longstanding puzzles like B → πK are also discussed. The Z ′-boson masses required to address the observed anomaly lie in the range of 7 TeV. Such heavy Z ′ bosons evade the existing bounds from precision data and direct searches, and will remain difficult to discover even at a high-luminosity LHC. The potential of an ILC as well as the next generation of low-energy parity-violation experiments in constraining the Z ′-boson parameter space is also examined.