Speaker
Description
Among the several models proposed to explain the nature of Dark Matter (DM), several scenarios predict the existence of a larger Dark Sector. In this context, a new strongly-coupled, SU(2) dark flavour symmetry conserving model can be theorized as the ???dark??? counterpart of Standard Model QCD, leading to composite dark mesons or baryons as possible DM candidates. The vector-like fermions of this new Dark Sector can interact also with the electroweak and Higgs SM sectors. As long as their mass is dominant over the chiral mass, the new Dark Sector is only weakly constrained by precision electroweak or Higgs coupling measurements, while the Dark Sector global symmetry breaking provided by the Higgs interactions allow dark mesons to decay into pure SM states. In this poster, the first dedicated search at colliders for dark mesons decaying into SM final states is presented. The analysis relies on the full Run 2 dataset of proton-proton collisions at 13 TeV, collected by the ATLAS experiment at the Large Hadron Collider. A simplified model with dark rhos and dark pions triplet is considered, where dark pions are pair-produced through dark rhos decay, and further decay gaugephobically into top and bottom quarks. The analysis targets tttb and ttbb final states in the all-hadronic or 1-lepton channels, which will eventually be combined.
