  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 TeV is presented.
Data were collected with the CMS detector at the LHC, corresponding to an
integrated luminosity of 35.9 fb$^{-1}$. The search is performed for resonances
with a mass between 0.8 and 3.5 TeV using events in which one Higgs boson
decays into a bottom quark pair and the other decays into two W bosons that
subsequently decay into a lepton, a neutrino, and a quark pair. The Higgs boson
decays are reconstructed with techniques that identify final state quarks as
substructure within boosted jets. The data are consistent with standard model
expectations. Exclusion limits are placed on the product of the cross section
and branching fraction for generic spin-0 and spin-2 massive resonances. The
results are interpreted in the context of radion and bulk graviton production
in models with a warped extra spatial dimension. These are the best results to
date from searches for an HH resonance decaying to this final state, and they
are comparable to the results from searches in other channels for resonances
with masses below 1.5 TeV.
