Grant: Subatomic Physics Envelope - Individual

The Standard Model(SM) of particle physics gives a description of all the particles and forces known to date. Over the past 50 years it has been tested to exquisite precision. The theoretical description of the Standard Model is based on an elegant symmetry principle. It allows to describe of all interactions in term of only three parameters, namely the gauge coupling constants. However, the same principle predicts that all the particles of the SM should be massless. This is not the case, which means that the symmetry must somehow be broken. This phenomenon is called electroweak symmetry breaking(EWSB) and the physics responsible for it remains to a large extend unknown and uncovering it has been one of the main quests of high energy physics, both theoretical and experimental for the past two or three decades. The Large Hadron Collider now in operation in CERN near Geneva Switzerland has been built with this objective in mind. It is a circular accelerator with a circumference of 27km that collides two beams of protons with very high energy (each beam has now an energy of 4 TeV). Two detectors that record the complicated results of the collisions have recently discovered what seem to be the Higgs boson and the announcement of this discovery was made public in June of 2012, creating a lot of excitement, for particle physicists in particular, but for the general public as well. While the Higgs field offers a good description of EWSB, the quest to fully understand it is far from over. For example, the SM with a single Higgs boson requires a very precise fine-tuning of parameters. It also, among other things, doesn't give an explanation for the observation of dark matter, or explain the structure of the different masses and mixing of the SM particles.My research program tries to understand some of these issues by proposing alternatives theories of EWSB. For example, I am studying supersymmetric models and Little Higgs models. Those theories predict new particles and/or forces that could be seen at LHC. In various research projects I propose to build new models that offer solutions to the shortcomings of the SM, and study their consequences for what the LHC might observe.