Resonant third-generation leptoquark signatures at the Large Hadron Collider

TL;DR

This paper proposes new LHC search strategies for third-generation leptoquarks, focusing on resonant signals involving bottom quarks, tau leptons, top quarks, and missing energy, to better explore B-physics anomalies.

Contribution

It introduces novel analysis methods for LHC searches targeting leptoquark signatures beyond strong production, emphasizing quark-lepton annihilation channels and providing sensitivity evaluations.

Findings

Stringent constraints on third-generation vector leptoquark masses and couplings.

Potential to probe interesting parameter space addressing B-physics anomalies.

Recommendations for dedicated resonance searches in the $b + \tau$ final state.

Abstract

Given the hints of lepton-flavour non-universality in $B$-meson decays, leptoquarks (LQs) are enjoying a renaissance. We propose novel Large Hadron Collider (LHC) searches for such hypothetical states that do not rely on strong production only, but can also receive important contributions from quark-lepton annihilation. For the cases of a resonant signal involving a bottom quark and a tau lepton ($b + \tau$), a top quark and missing transverse energy ($E_{T}^{\rm miss}$) and light-flavour jets plus $E_{T}^{\rm miss}$, we develop realistic analysis strategies and provide detailed evaluations of the achievable sensitivities for the corresponding LQ signatures at future LHC runs. Our analyses allow us to derive a series of stringent constraints on the masses and couplings of third-generation singlet vector LQs, showing that at LHC Run III and the high-luminosity LHC the proposed search channels can probe interesting parts of the LQ parameter space addressing the $B$-physics anomalies. In view of the reach of the proposed $b + \tau$ signature, we recommend that dedicated resonance searches for this final state should be added to the exotics search canon of both ATLAS and CMS.