Observation of vector-boson-fusion production of Higgs bosons in the H → WW ∗ → eνμν decay channel in pp collisions at √ s = 13 TeV with the ATLAS detector

An observation of vector-boson-fusion (VBF) production of Higgs bosons in the H→WW∗→eνμν decay channel is presented. The proton-proton collision data used to obtain this result were produced at the LHC with a center-of-mass energy of 13 TeV and recorded with the ATLAS detector between 2015 and 2018, corresponding to an integrated luminosity of 139fb−1139fb−1. The signal is observed (expected) with a significance of 7.0 (6.2) standard deviations. The product of the total VBF cross-section times the H→WW∗ branching fraction is measured to be 0.85±0.10(stat.)+0.17−0.13(syst.)pb0.85±0.10(stat.)−0.13+0.17(syst.)pb, compatible with the Standard Model prediction of 0.81±0.020.81±0.02 pb.