Search for Dark Matter Produced in Association with a Dark Higgs Boson in the b¯b Final State Using pp Collisions at √s = 13 TeV with the ATLAS Detector

Abstract

A search is performed for dark matter particles produced in association with a resonantly produced pairof b-quarks with 30 < mbb < 150 GeV using 140 fb-1 of proton-proton collisions at a center-of-massenergy of 13 TeV recorded by the ATLAS detector at the LHC. This signature is expected in extensions ofthe standard model predicting the production of dark matter particles, in particular those containing a darkHiggs boson s that decays into b-b. The highly boosted s RIGHTWARDS ARROW b-b topology is reconstructed using jetreclustering and a new identification algorithm. This search places stringent constraints across regions ofthe dark Higgs model parameter space that satisfy the observed relic density, excluding dark Higgs bosonswith masses between 30