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

Abstract

International audienceA search for the exotic decay of the Higgs boson (H) into a b$\overline{b}$ 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 $\sqrt{s}$ = 13 TeV. The search targets events from ZH production in an NMSSM scenario where H → ${\overset{\sim }{\chi}}_2^0{\overset{\sim }{\chi}}_1^0$, with ${\overset{\sim }{\chi}}_2^0$→$a{\overset{\sim }{\chi}}_1^0$, where a is a light pseudoscalar Higgs boson and ${\overset{\sim }{\chi}}_{1,2}^0$ 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 branching ratio for a three-dimensional scan of the masses of the ${\overset{\sim }{\chi}}_2^0$, ${\overset{\sim }{\chi}}_1^0$ and a boson.[graphic not available: see fulltext