Cornering Scalar Leptoquarks at LHC

TL;DR

This paper investigates the potential for detecting scalar leptoquarks at the LHC by analyzing flavor constraints, production mechanisms, and recasting existing searches, leading to improved limits on their couplings.

Contribution

It provides a comprehensive analysis of large leptoquark couplings, includes t-channel and single production mechanisms, and sets new limits based on recast LHC data.

Findings

Leptoquarks can have sizeable couplings to SM fermions.

Inclusion of t-channel and single production enhances search sensitivity.

New best limit on second-generation leptoquark coupling to muon and strange quark.

Abstract

We study implications of large lepton-quark-leptoquark couplings for direct leptoquark searches at Large Hadron Collider. We present all existing flavor constraints on the strength of these couplings assuming that leptoquarks under consideration interact exclusively with charged leptons and quarks of the same generation. We find that these leptoquarks can have sizeable couplings to the Standard Model fermions. This insures a self consistency of our study. We discuss the leptoquark production mechanisms at LHC and demonstrate the importance of inclusion of a t-channel pair production and, in particular, a single leptoquark production through a recast of an existing CMS search at LHC for the second generation leptoquark. Our recast yields the best direct limit on Yukawa coupling of the second generation leptoquark that couples to a muon and a strange quark to date.