Search for Higgs Boson Pair Production in Proton-Proton Collision Data at $\sqrt{S} =13$ TeV Using the ATLAS Detector at the Large Hadron Collider

A search is presented for Higgs boson pair production in the $b \bar{b}WW^{*}$ final state in which one $W$ boson decays leptonically (to an electron or a muon plus a neutrino) and the other $W$ boson decays hadronically. The analysis is performed using an integrated luminosity of 13.2 fb$^{-1}$ of $pp$ collision at $\sqrt{s}= 13$ TeV collected by ATLAS detector at the LHC. No evidence of events beyond the background expectation is found. Limit on the production cross section of $hh$ having invariant mass 400 GeV is obtained at $95\%$ confidence level.