Distinguishing signatures of scalar leptoquarks at hadron and muon colliders

TL;DR

This paper investigates how scalar leptoquarks could be detected at current and future colliders, analyzing their signatures and sensitivities through simulations at the LHC, FCC, and muon colliders.

Contribution

It provides a detailed simulation-based analysis of scalar leptoquark signatures at various colliders, highlighting optimal detection channels and mass reach.

Findings

Mono-b-jet + missing energy is the best signal at 30 TeV LHC and FCC.

c-jet + two tau-jets can probe Yukawa couplings down to 0.1 for 3 TeV leptoquarks.

Muon collider can probe leptoquark couplings at 0.1 for 5 TeV mass.

Abstract

While the hunt for new states beyond the standard model (SM) goes on for various well motivated theories, the leptoquarks are among the most appealing scenarios at recent times due to a series of tensions observed in $B$-meson decays. We consider $SU(2)$ singlet and triplet scalar leptoquarks separately, which contribute to charged and neutral current $B$-meson decays. Focusing on the single production of these two scalar leptoquarks, we perform a PYTHIA-based simulation considering all the dominant SM backgrounds at the current and future setups of the Large Hadron Collider (LHC). The mono-$b$-jet + $\ptmiss$ finalstate gives the strongest signal for the singlet leptoquark at the 30 TeV LHC or Future Circular Collider (FCC), with a possibility of $5\sigma$ signal significance with $\gtrsim 1000$ \fbi of integrated luminosity, for the chosen benchmark scenarios. The finalstate consisting of a $c$-jet and two $\tau$-jets provides highest reach for the singlet leptoquark, probing an $\mathcal{O}(10^{-1})$ value of the Yukawa-type couplings for up to $3.0$ TeV leptoquark mass. For the triplet leptoquark, $1-{\rm jet}+2\mu + \ptmiss$ topology is the most optimistic signature at the LHC, probing leptoquark couplings to fermions at $\mathcal{O}(10^{-1})$ value for the leptoquark mass range up to $ 4.0$ TeV. The invariant mass edge distribution is found to be instrumental in determination of the leptoquark mass scale at the LHC. We also perform the analysis at the proposed multi-TeV muon collider, where an $\mathcal{O}(10^{-1})$ leptoquark Yukawa coupling can be probed for a $5.0$ TeV leptoquark mass.