On precise probing of inert Higgs doublet model at the LHC

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 (LHC). We take into account ${\cal{O}}(\alpha_s)$ corrections to the gluon-gluon-Higgs effective coupling wherever appropriate. We find such corrections have a significant impact on various kinematic distributions and reduce scale uncertainties substantially. We match fixed order NLO results to {\sc Pythia8} parton shower (PS) and examine the di-fatjet signal associated with the missing transverse momentum, as this 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 dynamic 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.