One Leptoquark to Rule Them All: A Minimal Explanation for $R_{D^{(*)}}$, $R_K$ and $(g-2)_\mu$

Abstract

We show that by adding a single new scalar particle to the Standard Model, a TeV-scale leptoquark with the quantum numbers of a right-handed down quark, one can explain in a natural way three of the most striking anomalies of particle physics: the violation of lepton universality in $\bar B\to\bar K\ell^+\ell^-$ decays, the enhanced $\bar B\to D^{(*)}\tau\bar\nu$ decay rates, and the anomalous magnetic moment of the muon. Constraints from other precision measurements in the flavor sector can be satisfied without fine-tuning. Our model predicts enhanced $\bar B\to\bar K^{(*)}\nu\bar\nu$ decay rates and a new-physics contribution to $B_s\!-\!\bar B_s$ mixing close to the current central fit value.