Search for Higgs boson pair production with one associated vector boson in proton-proton collisions at $\sqrt{s}$ = 13 TeV

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 $\mathrm{b}\bar{\mathrm{b}}\mathrm{b}\bar{\mathrm{b}}$ 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, ${\kappa }_{\lambda }$, assuming ${\kappa }_{2\mathrm{V}}$ = 1 and vice versa on the coupling of two Higgs bosons with two vector bosons, ${\kappa }_{2\mathrm{V}}$. The observed (expected) 95% confidence intervals of these coupling modifiers are -37.7 $<$ ${\kappa }_{\lambda }$ $<$ 37.2 (-30.1 $<$ ${\kappa }_{\lambda }$ $<$ 28.9) and -12.2 $<$ ${\kappa }_{2\mathrm{V}}$ $<$ 13.5 (-7.2 $<$ ${\kappa }_{2\mathrm{V}}$ $<$ 8.9), respectively.