Advancing LHC Probes of Dark Matter from the Inert 2-Higgs Doublet Model with the Mono-jet Signal

TL;DR

This paper enhances the search for dark matter within the inert 2-Higgs Doublet Model at the LHC by using shape analysis of mono-jet signals and full one-loop computations to improve detection prospects.

Contribution

It introduces a shape analysis method for mono-jet signals and assesses the validity of the effective vertex approximation using full one-loop calculations.

Findings

Shape analysis significantly improves LHC discovery potential.

Full one-loop computation reveals important differences from effective vertex approximation.

Projected LHC sensitivity to i2HDM parameter space is enhanced.

Abstract

The inert 2-Higgs Doublet Model (i2HDM) is a well-motivated minimal consistent Dark Matter (DM) model, but it is rather challenging to test at the Large Hadron Collider (LHC) in the parameter space allowed by relic density and DM direct detection constraints. This is especially true when considering the latest XENON 1T data on direct DM searches which we use here to present the best current combined limit on the i2HDM parameter space. In this analysis, we present prospects to advance the exploitation of DM mono-jet signatures from the i2HDM at the LHC, by emphasising that a shape analysis of the missing transverse momentum distribution allows one to sizably improve the LHC discovery potential. As a key element of our analysis, we explore the validity of using an effective vertex, $ggH$, for the coupling of the Higgs boson to gluons using a full one-loop computation. We have found sizeable differences between the two approaches, especially in the high missing transverse momentum region, and incorporated the respective K-factors to obtain the correct kinematical distributions. As a result, we delineate a realistic search strategy and present the improved current and projected LHC sensitivity to the i2HDM parameter space.