Abstract
Abstract:
A search for the decay of the Standard Model Higgs boson into a bb¯ pair when produced in
association with a W or Z boson is performed with the ATLAS detector. The data, corres- ponding to
an integrated luminosity of 79.8 fb−1 were collected in proton–proton collisions during Run 2 of
the Large Hadron Collider at a centre-of-mass energy of 13 TeV. For a Higgs boson mass of 125 GeV,
an excess of events over the expected background from other Stand- ard Model processes is found
with an observed (expected) significance of 4.9 (4.3) standard deviations. A combination with the
results from other searches in Run 1 and in Run 2 for the Higgs boson in the bb¯ decay mode is
performed, which yields an observed (expected) significance of 5.4 (5.5) standard deviations, thus
providing direct observation of the Higgs boson decay into b-quarks. The ratio of the measured
event yield for a Higgs boson decaying
into bb¯ to the Standard Model expectation is 1.01 ± 0.12(stat.)
(syst.). Additionally, a
combination of Run 2 results searching for the Higgs boson produced in association with a
vector boson yields an observed (expected) significance of 5.3 (4.8) standard deviations.