Manifestations of Dark Matter in processes with three and four Top-Quarks

Abstract

This study explores possible manifestations of Dark Matter (DM) in processes involving multiple top quarks at the LHC. We analyze both the associated production of scalar and pseudoscalar DM Mediators with up to four top quarks, as well as their resonant production in top-rich final states, within a simplified model framework. Cross sections were calculated using the CompHEP and MadGraph packages with benchmark parameters recommended by the LHC Dark Matter Working Group. A detailed comparison of differential cross sections for key kinematic observables in three- and four-top-quark production demonstrates pronounced deviations from Standard Model predictions. The results highlight the limited feasibility of associated production channels, while resonant DM Mediator production offers realistic discovery prospects. Overall, the analysis underscores the potential of multi-top-quark final states as sensitive probes of Dark Matter at current and future collider experiments.

Figures (6)

• Figure 1: Representative diagrams for the associative production of a scalar and pseudoscalar DM Mediator with one (a) and two (b,c) top quarks.
• Figure 2: Representative diagrams for resonant production of a DM Mediator for two top-quark final states.
• Figure 3: Representative diagrams for resonant production of a DM Mediator for three- (a,b) and four-top-quark (c,d) final states.
• Figure 4: Distributions of invariant masses for all possible top-antitop pairs in the process $gg \to t\bar{t}tW^{-}\bar{b}$, ordered in descending order: $M_1(t\bar{t})$ (largest mass), $M_2(t\bar{t})$ , $M_3(t\bar{t})$ , and $M_4(t\bar{t})$ (smallest mass). The Standard Model process (red curve), the combined contribution of the Standard Model and the Dark Matter model with a scalar DM Mediator (green curve), and the full process including interference effects between the Standard Model and Dark Matter (blue curve).
• Figure 5: Normalized differential cross sections for $\text{Min } M(t\bar{t})$, $\text{Max } M(t\bar{t})$, $\hat{s}$. The Standard Model process (red curve), the Dark Matter model with a scalar DM Mediator (blue curve).