Precise probing of the inert Higgs-doublet model at the LHC

TL;DR

This paper investigates the impact of next-to-leading order QCD corrections on the inert Higgs-doublet model at the LHC, focusing on improved predictions for dark matter and scalar signals, and refining analysis strategies.

Contribution

It provides the first detailed NLO QCD correction analysis for the inert Higgs-doublet model, including matching to parton showers and implications for LHC search strategies.

Findings

NLO corrections significantly alter kinematic distributions.

Scale uncertainties are substantially reduced with NLO corrections.

The di-fatjet plus missing transverse momentum channel is promising for probing the model.

Abstract

The inert Higgs-doublet model provides a simple framework to accommodate a viable Higgs portal scalar dark matter candidate, together with other heavier scalars of mass 100 GeV or more. We study the effect of next-to-leading order (NLO) QCD corrections in this scenario in the context of the Large Hadron Collider. ${\cal{O}}(\alpha_s)$ corrections to the gluon-gluon-Higgs effective coupling have been taken into account in this study wherever appropriate. We find such corrections have a significant impact on various kinematic distributions and reduce scale uncertainties substantially. Fixed order NLO results are matched to the {\sc Pythia8} parton shower (PS) and the di-fatjet signal associated with the missing transverse momentum is analyzed, as this channel has the ability to explore its entire parameter space during the next phase of the LHC run. A closer look at the NLO+PS computation indicates a sizable NLO effect together with a subdued contribution from associated production of the heavy scalar compared to the pair production, thereby leading to a refined analysis strategy during the multivariate analysis of this signal.