Detecting multimuon jets from the Higgs boson exotic decays in the Higgs portal framework

A muon jet (μ-jet) is a very special feature that consists of a cluster of collimated muons from the decay of a fast-moving light particle of mass about O(1 GeV). We will use this feature to search for very light particles from rare decays of the Higgs boson. For such a small angular separation of muons which might come from a long-lived particle, both ATLAS and CMS could have the displaced-vertexing-reconstruction capability. We use two simple models of the Higgs portal type to explore the possibilities of event topologies with two 2μ-jets, one 2μ-jet and one 4μ-jet, and two 4μ-jets in the final state at LHC-14. We also summarize existing constraints on these models.