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

The collaboration
JHEP 01 (2022) 063, 2022.

Abstract (data abstract)
CERN-LHC, ATLAS. A search for the exotic decay of the Higgs boson ($H$) into a $b\bar{b}$ resonance plus missing transverse momentum is described. The search is performed with the ATLAS detector at the Large Hadron Collider using $139\; \mathrm{fb}^{-1}$ of $pp$ collisions at $\sqrt{s} = 13$ TeV. The search targets events from $ZH$ production in an NMSSM scenario where $H \rightarrow\tilde{\chi}_{2}^{0}\tilde{\chi}_{1}^{0}$, with $\tilde{\chi}_{2}^{0} \rightarrow a \tilde{\chi}_{1}^{0}$, where $a$ is a light pseudoscalar Higgs boson and $\tilde{\chi}^{0}_{1,2}$ 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 $\tilde\chi_{2}^{0}$, $\tilde{\chi}_{1}^{0}$ and $a$ boson.