Measurements of WH and ZH production with Higgs boson decays into bottom quarks and direct constraints on the charm Yukawa coupling in 13 TeV pp collisions with the ATLAS detector

A study of the Higgs boson (H) decaying into bottom quarks (H→bbˉ) and charm quarks (H→ccˉ) is performed, in the associated production channel of the Higgs boson with a W or Z boson (VH), using 140 fb-1 of proton-proton collision data at sqrt(s)=13 TeV collected by the ATLAS detector at the LHC. The individual production of WH and ZH with H→bbˉ is established with observed (expected) significances of 5.3 (5.5) and 4.9 (5.6) standard deviations (σ), respectively, confirming the observation of both processes. Differential cross-section measurements of the gauge boson transverse momentum within the Simplified Template Cross-Section (STXS) framework are performed in a total of 13 kinematical fiducial regions. The search for the H→ccˉ decay yields an observed (expected) upper limit at 95% confidence level of 11.5 (10.6) times the Standard Model prediction. The results are also used to set constraints on the charm Yukawa coupling modifier (κc), resulting in ∣κc∣<4.2 at 95% confidence level. Finally, combining the H→bbˉ and H→ccˉ measurements constrains the absolute value of the ratio of Higgs-charm and Higgs-bottom coupling modifiers (∣κc/κb∣) to be less than 3.6 at 95% confidence level.