Search for the decay of the Higgs boson into two nMSSM pseudo-scalar particles

The next to minimal supersymmetric Standard Model predicts the existence of additional scalar and pseudo-scalar higgs particles in addition to the scalar boson predicted by the Standard Model. If one of them is lighter than the observed Higgs boson candidate, it could be produced in pairs in the decay of the observed Higgs boson or heavier scalar bosons. This talk presents searches in several final states, which are sensitive to different decay modes of the light new particles, using both 8 and 13 TeV ATLAS data.