Search for Associated Production of a Higgs Boson and Two Vector Bosons via Vector-Boson Scattering at sqrt[s]=13  TeV

A search for Higgs boson (H) production in association with two vector bosons (V=W, Z) via vector-boson scattering (VBS) is presented using proton-proton collision data collected at sqrt[s]=13  TeV by the CMS experiment, corresponding to an integrated luminosity of 138  fb^{-1}. Events containing two forward jets consistent with VBS, a large-radius jet from the decay of a boosted H to a pair of b quarks, and zero, one, or two charged leptons coming from V decays are selected. The process is excluded at 95% confidence level for observed (expected) values of the VVHH coupling modifier κ_{2V} outside the interval 0.40<κ_{2V}<1.60 (0.34<κ_{2V}<1.66), assuming standard model values for all other couplings, thus establishing a novel probe of the VVHH interaction. Constraints are also set on the individual κ_{2W} and κ_{2Z} coupling modifiers and on the allowed region in the κ_{2W}-κ_{2Z} plane.