Abstract:

The study of massive gauge vector bosons scattering (VBS) has always been a primary goal of the LHC physics program. Before an Higgs-cadidate particle was discovered, the expected violent raise of the longitudinally-polarized VBS amplitude with the center of mass energy has been used as a strong argument for new physics to enter at the ~TeV scale. The discovery of a 125 GeV Higgs boson suggests what mechanism unitarizes this amplitude. The study of VBS processes still provides a powerful way of testing the electroweak symmetry breaking sector of the Standard Model, complementary to the direct Higgs couplings measurements. The production of same-charge W bosons in association with jets (W+W+jj and charge-conjugate) represents the golden channel to study VBS at the LHC, thanks to the favorable signal/background ratio. No direct evidence of a process involving the scattering of four massive vector bosons was observed, either at LEP, Tevatron or LHC, until very recently. I will present the first evidence of electroweak production of W+W+jj and W-W-jj production from the analysis of 20.3/fb of proton-proton collision data at s^{1/2}=8 TeV collected by the ATLAS experiment at the LHC. The experimental challenges and results of this measurement will be presented and I will conclude with the future prospects for VBS measurements in the coming years of operations of the LHC.