U 2 0 1 5 ) 0 5 1 Scalar leptoquarks at LHC
The implications of large lepton-quark-leptoquark couplings for direct leptoquark searches at Large Hadron Collider (LHC) are addressed. It is shown that flavour physics constraints allow for sizeable couplings of leptoquarks to the Standard Model fermions if these interact exclusively with charged leptons and quarks of the same generation. The leptoquark production mechanisms at LHC are thoroughly discussed to demonstrate the importance of inclusion of a t-channel pair production and, in particular, a single leptoquark production if and when the leptoquark couplings are large. A recast of an existing CMS search at LHC for the second generation leptoquarks is accordingly presented. It is shown to yield the best direct limit to date on Yukawa coupling of a leptoquark that couples exclusively to a muon and a strange quark .