Expected sensitivity of the ATLAS experiment to H→b¯b and H→c¯c decays in the VH production mode at the High Luminosity LHC

The expected precision of studies of Higgs-boson decays to bottom and charm quarks in associated production with a W or Z boson with the ATLAS detector at the High-Luminosity LHC are estimated, assuming a proton-proton collision dataset corresponding to 3000 fb−1 collected at a centre-of-mass energy of √s=14 TeV. The existing combined probe of these processes using a proton-proton collision dataset of 140 fb−1 at √s=13 TeV is extrapolated to High-Luminosity LHC conditions, by scaling luminosity and centre-of-mass energy, and considering several scenarios of systematic uncertainties. The impact of improvements in jet-flavour-identification techniques is studied as well. For the measurements of ZH and WH production in Higgs-boson decays to bottom quarks, the projected uncertainties on the signal strength measurements are around 7%. Additionally, extrapolations of fiducial cross-section measurements in the context of the Simplified Template Cross-Section framework are performed, where the expected precision in the various transverse momenta and jet multiplicity ranges varies between 8% and 40%. For Higgs-boson decays to charm quarks, an expected upper limit of 2.2 times the predicted cross-section times branching ratio is estimated at the 95% confidence level. This sensitivity corresponds to a significance of 0.9 standard deviations above the background-only hypothesis. For a scenario with assumed improved jet-flavour-identification techniques a further increase of 30% is expected for the sensitivity to Higgs-boson decays to charm quarks.