Search for exotic decays of the Higgs boson into b$$\overline{b}$$ and missing transverse momentum in pp collisions at $$\sqrt{s}$$ = 13 TeV with the ATLAS detector
A bstract A search for the exotic decay of the Higgs boson ( H ) into a b $$\overline{b}$$ b ¯ 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 $$\sqrt{s}$$ s = 13 TeV. The search targets events from ZH production in an NMSSM scenario where H → $${\overset{\sim }{\chi}}_2^0{\overset{\sim }{\chi}}_1^0$$ χ ~ 2 0 χ ~ 1 0 , with $${\overset{\sim }{\chi}}_2^0$$ χ ~ 2 0 → $$a{\overset{\sim }{\chi}}_1^0$$ a χ ~ 1 0 , where a is a light pseudoscalar Higgs boson and $${\overset{\sim }{\chi}}_{1,2}^0$$ χ ~ 1 , 2 0 are the two lightest neutralinos. The decay of the a 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 more »