Asymmetric Leptoquark Pair Production at LHC

Abstract

We investigate asymmetric leptoquark pair production mechanism at the Large Hadron Collider to advocate its potential relevance to establish reliable constraints on the leptoquark parameter space and its ability to aid in correct identification of these attractive sources of new physics. The main feature of asymmetric pair production that genuinely distinguishes it from the usual leptoquark pair production is given by the fact that the two leptoquarks that are produced in proton-proton collisions through a $t$-channel lepton exchange are not charge conjugates of each other. Hence the proposed name of asymmetric leptoquark pair production for this type of process. We spell out prerequisite conditions for the asymmetric leptoquark pair production mechanism to be operational and enumerate all possible combinations of leptoquark multiplets that can potentially generate it. We finally reinterpret existing leptoquark pair production search results within several simple scalar leptoquark extensions of the Standard Model, assuming that the leptoquarks exclusively couple to either electrons or muons and the first generation quarks, to demonstrate proper inclusion of asymmetric pair production. We consequently present accurate parameter space constraints for the $S_1$, $S_3$, $R_2$, $S_1$+$S_3$, and $S_1$+$R_2$ leptoquark scenarios.