Impact of theory uncertainties related to Higgs boson production in the $H\rightarrow Z Z^{*}\rightarrow 4l$ and the $t\bar{t}H$ channels with the ATLAS detector at the HL-LHC

A study is presented on the impact of theory uncertainties related to the Higgs boson production in the $H \rightarrow Z Z^{*} \rightarrow 4l$, $t\bar{t}H,H\rightarrow \gamma\gamma$ and $t\bar{t}H$ multi-leptons channels, using 14 TeV proton-proton collisions at the High Luminosity LHC with 3000 $fb^{-1}$. This document is released coincident with the June 2018 HL/HE-LHC workshop and lists the main signal theory systematic uncertainties which limit the possible gain in precision for measurements using the expected large datasets. Only results for the $H{\rightarrow}Z Z^{*} \rightarrow 4l$ , $t\bar{t}H$ multi-lepton and $t\bar{t}H, H\rightarrow \gamma\gamma$ channels are presented as example of measurements that will reach a good precision at HL-LHC. The results here shown have been extrapolated from the published Run 2 results with 36 $fb^{-1}$, taking into account the increase of cross sections and luminosity at HL-LHC, and considering the same systematic uncertainties as in the published analysis.