Search for Higgs Boson pair production in the $b\bar{b}WW*$ channel in $\sqrt{s} = 13$ TeV proton-proton collisions at the Large Hadron Collider using the ATLAS detector

This dissertation presents a search for double Higgs production in the b ̄bWW∗ final state in proton-proton collisions at the ATLAS detector at the Large Hadron Collider. Double Higgs production is predicted in the Standard Model with a cross section of σHH = 33.53fb +4.3% ± 5.9%. Many Beyond the Standard Model theories −6.0% predict enhancements to the production cross section through resonant production. The 2015-2016 ATLAS dataset has an integrated luminosity of 36.1 fb-1 with a center of mass energy of √s = 13 TeV. Candidate events are broken into two kinematic regions: a resolved selection containing one lepton (either an electron or muon), 2 b-tagged calorimeter jets, 2 light-flavor jets, and missing transverse energy; and a boosted analysis containing one lepton (electron or muon), two large radius jets, one with two ghost associated, b-tagged track-jets and missing transverse energy. No significant deviation from background was observed a cross section upper limit was set for the SM double Higgs production of 10 pb and for resonant production as a function of HH invariant mass from 500 GeV to 3000 GeV. This dissertation includes previously published coauthored material.