Physics Colloquium: Symmetry Breaking: from QCD to the Higgs Boson and Beyond

Abstract:

A recurrent theme in fundamental physics is the search for symmetries, and how they are broken. In the case of the strong interactions, the lightness of the pion is due an approximate chiral symmetry of QCD, that also gives insights into the structure of the proton and neutron. Could a similar mechanism play a role in the breaking of electroweak symmetry, with the Higgs boson resembling a "heavy pion”? If so, might the dark matter in the Universe be provided by a corresponding analogue of the proton and neutron?