Electroweak Physics

One of the most important issues in contemporary particle physics is whether nature makes use of the Higgs mechanism of spontaneous symmetry breaking to generate the masses of gauge bosons and fermions. In the Standard Model the Higgs boson is the observable relic of the electroweak symmetry breaking mechanism. Its couplings to gauge bosons and fermions are fixed. However its mass and its self-coupling, which depends on its mass, are essentially unspecified.

There are various theoretical arguments to place upper bounds on the Higgs boson mass. Probability conservation in weak boson scattering at high energy requires its mass to be less than 1 TeV. The non-detection of Higgs signals at the Large Electron Positron Collider (LEP) rules out the mass range below 106 GeV at 95% confidence level.

The goals of Higgs physics at future colliders are:

1. to search the range not excluded by LEP

2. if Higgs boson(s) are discovered, to measure their couplings

3. if the Higgs boson is light, to check that the scattering of longitudinal weak bosons is small as then predicted.

A continuing research effort of our group is a comprehensive phenomenological study of Higgs boson production and its decays and the development of techniques to separate the Higgs signal from backgrounds at present and future colliders. Gauge boson self-interactions as a probe of the electroweak symmetry breaking sector are also topics under our investigation.