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Abstract

A study of the Higgs boson decaying into bottom quarks (H → b ¯b) and charm quarks (H → cc¯) is performed, in the associated production channel of the Higgs boson with a W or Z boson, using 140 fb−1 of proton-proton collision data at √ s = 13 TeV collected by the ATLAS detector. The individual production of W H and ZH with H → b ¯b is established with observed (expected) signifcances of 5.3 (5.5) and 4.9 (5.6) standard deviations, respectively. Diferential cross-section measurements of the gauge boson transverse momentum within the simplifed template cross-section framework are performed in a total of 13 kinematical fducial regions. The search for the H → cc¯ decay yields an observed (expected) upper limit at 95% confdence level of 11.5 (10.6) times the Standard Model prediction. The results are also used to set constraints on the charm coupling modifer, resulting in |κc| < 4.2 at 95% confdence level. Combining the H → b ¯b and H → cc¯ measurements constrains the absolute value of the ratio of Higgs-charm and Higgs-bottom coupling modifers (|κc/κb|) to be less than 3.6 at 95% confdence level.