A model for the Singlet-Triplet Leptoquarks

TL;DR

This paper proposes a composite Higgs model with scalar singlet and triplet leptoquarks to explain B-meson decay anomalies, analyzing flavor constraints and predicting leptoquark masses around 2-3 TeV.

Contribution

It introduces a strongly interacting resonance model where leptoquarks and the Higgs are Nambu-Goldstone bosons, addressing B-decay anomalies within flavor and electroweak bounds.

Findings

Leptoquarks with masses 2-3 TeV are naturally expected.

A tension of 10-25% tuning is needed to reconcile anomalies with flavor constraints.

The model provides a potential explanation for B-meson decay deviations.

Abstract

The deviations of $B$-meson decays measured in $R_{D^{(*)}}^{\tau\ell}$ and $R_{K^{(*)}}^{\mu e}$ can be explained by the presence of two scalar leptoquarks, a singlet $S_1$ and a triplet $S_3$, mostly coupled to the third generation. We consider a theory of resonances, as an effective description of a strongly interacting theory, that generates the leptoquarks and the Higgs as Nambu-Goldstone bosons, with the rest of the resonances at a scale of order $10-30\ {\rm TeV}$. We assume anarchic partial compositeness for the flavor of the SM fermions. Under these hypothesis we study whether it is possible to reproduce the deviations in the $B$-decays without being in conflict with flavor and electroweak bounds. We find a tension between $R_{D^{(*)}}^{\tau\ell}$ and some flavor observables, dominated by flavor violating $\tau$ decays and $\Delta m_{B_s}$, that require a tuning of order $10-25\%$. We also compute the potential of the scalars showing that leptoquarks with masses ${\cal}O(2-3)\ {\rm TeV}$ can be naturally expected in the model. We discuss briefly the phenomenology of the other resonances.