Search for a massive resonance decaying into a Higgs boson and a W or Z boson in hadronic final states in proton-proton collisions at sqrt(s) = 8 TeV

A search for a massive resonance decaying into a standard model Higgs boson (H) and a W or Z boson is reported. The analysis is performed on a data sample corresponding to an integrated luminosity of 19.7~fb$^{-1}$, collected in proton-proton collisions at a centre-of-mass energy of 8~TeV with the CMS detector at the LHC. Signal events in which the decay products of Higgs, W or Z bosons at high Lorentz boost are contained within a single reconstructed jet are identified using jet substructure techniques, including the tagging of b hadrons. This is the first search for heavy resonances decaying into HW or HZ resulting in an all-jets final state, as well as the first application of jet substructure techniques to identify ${\rm H\to WW^*\to 4q}$ decays at high Lorentz boost. No significant signal is observed and limits are set at the 95\% confidence level on the production cross section of W' and Z' in a model with mass-degenerate charged and neutral spin-1 resonances. Resonance masses are excluded for W' in [1.0, 1.6] TeV, for Z' in [1.0, 1.1], [1.3,1.5] TeV, and for mass-degenerate W' and Z' in [1.0, 1.7] TeV ranges.