Sensitivity to longitudinal vector boson scattering and doubly-charged Higgs boson production in $\mathbf{W^\pm W^\pm jj}$ at future hadron colliders
We study the sensitivity to longitudinal vector boson scattering at a 27, 50 and 100 TeV $pp$ collider using events containing two leptonically-decaying same-electric-charge $W$ bosons produced in association with two jets. The baseline FCC-hh detector parameterization within the Delphes framework is used under the assumption of fully efficient pile-up mitigation. A tightly constrained phase space with a dijet mass greater than 2 TeV is considered in order to suppress the impact of potential instrumental backgrounds. Based on this setup, the expected sensitivity to the production of longitudinally polarized same-sign $W$ boson pairs is evaluated. Additionally, expected limits are set on doubly charged Higgs bosons produced via vector boson fusion processes and decaying to same-sign $W$ boson pairs.