Search for exotic decays of the Higgs boson into bb¯ and missing transverse momentum in pp collisions at √s = 13 TeV with the ATLAS detector

Abstract

A search for the exotic decay of the Higgs boson (H) into a bb¯¯ resonance plus missing transverse momentum is described. The search is performed with the ATLAS detector at the Large Hadron Collider using 139 fb⁻¹ of pp collisions at s√ = 13 TeV. The search targets events from ZH production in an NMSSM scenario where H → χ∼(0)(2)χ(∼0)(1), with χ(∼0)(2) → aχ(∼0)(1), where a is a light pseudoscalar Higgs boson and χ(∼0)(1),2 are the two lightest neutralinos. The decay of the ɑ boson into a pair of b-quarks results in a peak in the dijet invariant mass distribution. The final-state signature consists of two leptons, two or more jets, at least one of which is identified as originating from a b-quark, and missing transverse momentum. Observations are consistent with Standard Model expectations and upper limits are set on the product of cross section times branching ratio for a three-dimensional scan of the masses of the χ(∼0)(2), χ(∼0)(1) and a boson.