SEMINAR

Gedanken Worlds without Higgs

Prof. Chris Quigg

(Fermilab, USA)

Sala P7, IST, Edifício Matemática
Tuesday, December 16th, 2008 at 04:00 PM

Abstract

What would the world be like, without a (Higgs) mechanism to hide electroweak symmetry and give masses to the quarks and leptons? To illuminate how electroweak symmetry breaking shapes the physical world, we investigate two classes of toy models in which no Higgs fields are introduced to induce spontaneous symmetry breaking. The models incorporate the standard-model gauge symmetry and fermion content similar to that of the standard model. In the first class, spontaneous breaking of chiral symmetry within quantum chromodynamics is the only source of electroweak symmetry breaking. The second class adds bare fermion masses sufficiently tiny that the model can serve as a well-behaved low-energy effective field theory to energies somewhat above the hadronic scale. The Higgsless models not only provide informative contrasts to the real world, but also lead us to consider our standard interpretations in a new light.