Single Leptoquark Solutions to the $B$-physics Anomalies

TL;DR

This paper investigates whether a single light leptoquark, specifically the vector leptoquark U_1, can simultaneously explain the B-physics anomalies by analyzing constraints from low-energy experiments and LHC searches.

Contribution

The study identifies the vector leptoquark U_1 as the only single leptoquark model capable of explaining both B-physics anomalies simultaneously, considering current experimental constraints.

Findings

U_1 is the only viable single leptoquark model for both anomalies.

Improving bounds on B→Kμτ could challenge U_1's viability.

LHC and low-energy data are complementary in constraining models.

Abstract

We examine various scenarios in which the Standard Model is extended by a light leptoquark state to explain one or both $B$-physics anomalies. Combining low-energy constraints and direct searches at the LHC, we confirm that the only single leptoquark model that can explain both anomalies at the same time is a vector leptoquark, known as $U_1$. Focusing on $U_1$, we highlight the complementarity between LHC and low--energy constraints, and argue that improving the experimental bound on $\mathcal{B}(B\to K\mu\tau)$ by two orders of magnitude could compromise its viability as a solution to the $B$-physics anomalies.