Beyond the Higgs

by Grojean, C. (CERN-PH/TH)

Friday 9 Jun 2006, 14:00 → 15:00 Europe/Zurich

TH Auditorium (CERN)

How electroweak symmetry is broken is one of the pressing questions in particle physics that should find an answer in the next few years. It has recently driven many developments in model building. A radical alternative to the usual Higgs mechanism is to achieve electroweak symmetry breaking without any scalar boson. This idea can be realized in extra dimensions, where the standard model gauge symmetry is broken by boundary conditions. Such a proposal has to pass theoretical prejudices (unitarization of longitudinal W's scattering amplitude) as well as phenomenological obstacles (electroweak precision measurements which favour a priori the existence of a light Higgs, tension between a heavy top quark and small deviations in the Zbb coupling). At the LHC, this Higgsless mechanism leads to signatures very different from the standard model or supersymmetry and it predicts the existence below one TeV of spin-one excitations with the quantum numbers of the W and the Z.