Publication
A search for Higgs boson pair (HH) production in association with a vector boson V (W or Z boson) is presented. The search is based on proton-proton collision data at a center-of-mass energy of 13 TeV, collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 138 fb(-1). Both hadronic and leptonic decays of V bosons are used. The leptons considered are electrons, muons, and neutrinos. The HH production is searched for in the b (b) over barb (b) over bar decay channel. An observed (expected) upper limit at 95% confidence level of VHH production cross section is set at 294 (124) times the standard model prediction. Constraints are also set on the modifiers of the Higgs boson trilinear self-coupling, k(lambda), assuming k(2V) = 1, and vice versa on the coupling of two Higgs bosons with two vector bosons, k(2V). The observed (expected) 95% confidence intervals of these coupling modifiers are -37.7 < k(lambda) < 37.2 (-30.1 < k(lambda) < 28.9) and -12.2 < k(2V) < 13.5 (-7.2 < k(2V) < 8.9), respectively.