Vector Boson Scattering at high energy at the LHC

With present and upcoming colliders like the Tevatron and the Large Hadron Collider (LHC), the origin of electroweak symmetry breaking (EWSB) will be explored up to the TeV scale. In the absence of a light Higgs boson (SM or supersymmetry) vector boson scattering will be the best probe for the study of the mechanism of EWSB. Here a Chiral Lagrangian (ChL) Model, inspired by pion scattering, is used to extrapolate to what may happen at LHC energies in such case. This scenario is explored with simulation tools to evaluate the sensitivity of the ATLAS detector to new physics. We investigate W Z and Z Z scattering in various decay channels with full ATLAS detector simulation. Several techniques for event selection were developed: the study of heavy jets and their inner structure, forwardjet tagging and jet veto. A cut-based analysis was implemented using the selections tools mentioned. The very high QCD background associated to the signaIs studied, was fully taken into account for the first time in VBF studies, also with full simulation. We conc1ude that to be able to detect this signaIs with ATLAS we wouId need an integrated luminosity of about lOOfb-1 .