Heavy WIMP through Higgs portal at the LHC

Abstract

The LHC constraints on Higgs-portal WIMPs are studied. Scalar, vector and anti-symmetric tensor fields are considered. They are assumed to be heavier than a half of the Higgs boson mass. We investigate 8 TeV LHC results on signatures of the vector boson fusion, mono-jet and associated production of the Z boson, which proceed via virtual exchange of the Higgs boson. We show that the vector boson fusion channel gives the most stringent constraints on Higgs-portal interactions for all the WIMP models investigated here. The upper limits on vector and tensor Higgs-portal couplings can be 0.43 and 0.16 for the WIMP mass of 65 GeV, respectively. However, they are rapidly weakened for heavier WIMP masses, allowing O(1) couplings for masses heavier than ∼100 GeV. Constraints for scalar WIMPs are very weak. Prospects of the 14 TeV LHC are also discussed. We show that the constraints on the tensor and vector couplings would be improved by a factor of ∼1.5–2, depending on the search channels. It would be still challenging to constrain scalar WIMPs.