Search for resonances decaying to a pair of Higgs bosons in the $\text{b}\bar{\text{b}}\text{q}\bar{\text{q}}'\ell\nu$ final state in proton-proton collisions at $\sqrt{s}=13$ TeV

A search for new massive particles decaying into a pair of Higgs bosons in proton-proton collisions at a center-of-mass energy of $13~\mathrm{TeV}$ is presented. The result uses data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of $35.9~\mathrm{fb}^{-1}$. The search is performed for resonances in the mass range between $0.8$ and $3.5~\mathrm{TeV}$ for events in which one Higgs boson decays into a bottom quark pair ($\text{b}\bar{\text{b}}$) and the other decays into two $\mathrm{W}$ bosons that subsequently decay into a lepton, a neutrino, and a quark pair ($\text{q}\bar{\text{q}}'$). The former Higgs boson is reconstructed as a single jet with substructure consistent with a $\text{b}\bar{\text{b}}$ decay, and the latter as an isolated lepton and a nearby jet of merged $\text{W}\rightarrow\text{q}\bar{\text{q}}'$ decay products. The two-dimensional distribution of the $\text{b}\bar{\text{b}}$ jet mass versus the candidate resonance mass is used in a maximum likelihood fit to separate signal from background. The data are consistent with standard model expectations. Exclusion limits are placed on the product of cross section and branching fraction for spin-0 radions and spin-2 bulk gravitons in models with a warped extra spatial dimension.