On minimal Z' explanations of the B->K*mu+mu- anomaly

TL;DR

This paper explores minimal Z' models explaining the B->K*mu+mu- anomaly, revealing a model-independent triple-correlation among new physics effects, meson mixing, and CKM unitarity violations, with implications for future tests.

Contribution

It introduces a simple analytic relation linking new physics contributions in B decays, meson mixing, and CKM unitarity within minimal Z' models, enabling model-independent tests.

Findings

The triple-correlation relates NP in B->K*mu+mu- to B_s mixing and CKM unitarity.

The relation depends logarithmically on the Z' mass.

Future measurements can test the proposed NP pattern.

Abstract

Recently LHCb has announced a discrepancy of 3.7 sigma in one of the theoretically clean observables accessible through studies of angular correlations in B->K*mu+mu-. We point out that in the most minimal Z' setup that can address this anomaly there is a model-independent triple-correlation between new physics (NP) in B->K*mu+mu-, B_s-Bbar_s mixing, and non-unitarity of the quark-mixing matrix. This triple-correlation can be cast into a simple analytic formula that relates the NP contribution DeltaC9 to the Wilson coefficient of the semileptonic vector operator to a shift in the mass difference DeltaM_{B_s} and a violation of |Vud|^2+ |Vus|^2+ |Vub|^2 = 1. In contrast to the individual observables the found relation depends only logarithmically on the Z' mass. We show that that our findings allow for useful future tests of the pattern of NP suggested by the B->K*mu+mu- anomaly.