Dark Sector Searches Using Exotic Higgs Boson Decays in the ATLAS Collaboration

This Dark Sector search in the ATLAS collaboration uses Higgs boson exotic decays as a possible portal to such new phenomena. Use is made of the Standard Model (SM) decay to four leptons: H-->ZZ*-->4l The current analysis is sensitive to the possible existence of "Dark Sector" or "Hidden Sector" vector boson ("Zd") or pseudoscalar boson ("a") that is beyond the SM: H-->ZZd-->4l (electrons and muons) H-->Za-->4l ( models suggest that this is mainly to muons) Analysis results from the Run 2 dataset (15 inverse fb from 2016) and (21 inverse fb from 2015) will be presented.