$B$ anomalies and the tauphilic leptoquark model

TL;DR

This paper proposes three scalar leptoquarks coupling to third-generation leptons to explain B anomalies, with specific models fitting various decay ratios and constrained by meson mixing, predicting masses below 3 TeV for future collider tests.

Contribution

Introduction of a scalar leptoquark model with three particles explaining B anomalies and predicting collider-accessible masses, incorporating constraints from meson mixing and flavor universality violations.

Findings

Scalar singlet $S_1$ explains $R(D^{(*)})$

Doublet ${ ilde R}_2$ fits $B o K^{(*)} u{ar u}$

Masses below 3 TeV can be tested in future colliders

Abstract

We suggest three scalar leptoquarks, $S_1$, ${\tilde R}_2$, and $S_3$ which couple exclusively to the 3rd generation of leptons to explain the $B$ anomalies. The scalar singlet $S_1$ can explain $R(D^{(*)})$, while the doublet ${\tilde R}_2$ is needed to fit the branching ratio ${\rm Br}(B\to K^{(*)}\nu{\bar\nu})$ via the right-handed Wilson coefficients $C_R^\nu$. A strong constraint from $\Delta m_{B_s}$ requires triplet $S_3$ where the mixing term between $S_1$ and $S_3$ is important. Our analysis suggests subdominant $C_{V_L}<0$ and dominant $C_{S_L} >0$ and lepton-flavor universality violating $C_9^{\rm LQ} \approx +1$. The masses are expected to be $M_{S_1}\sim M_{{\tilde R}_2} < M_{S_3} \lesssim 3$ TeV, which can be probed in future colliders.