Studies of Vector Boson Scattering And Triboson Production with an Upgraded ATLAS Detector at a High-Luminosity LHC

The Phase 2 upgrade of the ATLAS detector would greatly increase the sensitivity to an extended electroweak symmetry-breaking sector beyond the Standard Model Higgs mechanism. A common feature of such an extended sector is the enhancement of vector boson scattering at high energy. Sensitivity to new physics is also gained through probing Quartic Gauge Boson Couplings via triboson production. Using detector performance parameterizations, we present the expected gain in sensitivity for ATLAS datasets with an integrated luminosity of 300/fb and $3000/fb at a center-of-mass energy of 14 TeV.