On Drell-Yan production of scalar leptoquarks coupling to heavy-quark flavours

• Main Authors: Haisch, Ulrich, Schnell, Luc, Schulte, Stefan
• Format: Journal Article
• Language: English
• Published: 30-10-2022
• Subjects: Physics - High Energy Physics - Experiment; Physics - High Energy Physics - Phenomenology
• DOI: 10.48550/arxiv.2207.00356

Given the hints of lepton-flavour non-universality in semi-leptonic $B$
decays, leptoquark (LQ) models with sizeable couplings to heavy-quark flavours
are enjoying a renaissance. While such models are subject to stringent
constraints from low-energy experiments also bounds from non-resonant dilepton
searches at the Large Hadron Collider (LHC) turn out to be phenomenologically
relevant. Based on the latest LHC dilepton analyses corresponding to an
integrated luminosity of around $140 \, {\rm fb}^{-1}$ of proton-proton
collisions at $\sqrt{s} = 13 \, {\rm TeV}$, we present improved limits on the
scalar LQ couplings that involve heavy-quark flavours and light or heavy
dileptons. In particular, we show that effects beyond the leading order that
are related to real QCD emissions are relevant in this context, since the
inclusion of additional heavy-flavoured jets notably improves the exclusion
limits that derive from the high-mass dilepton tails. The impact of electroweak
corrections and interference effects between signal and background is also
analysed. Within the POWHEG-BOX framework we provide a dedicated Monte Carlo
code that allows for an on-the-fly signal event generation including all the LQ
corrections considered in this article.