Speaker
Description
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. A dedicated Monte Carlo code within the {\tt POWHEG-BOX}~framework that allows for an on-the-fly signal event generation including all LQ corrections we considered is introduced.
