Search for resonances decaying to three W bosons in the hadronic final state at $\sqrt{s} = 13~\mathrm{TeV}$

A search for heavy resonances X decaying in cascade to three W bosons via a scalar radion R, $\mathrm{X} \to \mathrm{WR} \to \mathrm{WWW}$, with two or three massive, Lorentz-boosted jets is presented. The search is performed with proton-proton collision data recorded at $\sqrt{s} = 13~\mathrm{TeV}$ collected by the CMS experiment during 2016$-$2018, corresponding to an integrated luminosity of $137~\mathrm{fb}^{-1}$. Two final states are simultaneously probed, one where the two W bosons produced by the R decay are reconstructed as separate jets, and one where they are reconstructed as a single merged jet. The data observed are in agreement with the standard model expectations. Results are combined with a complementary and orthogonal search in the single-lepton channel to set the most stringent limits to date on the production cross section of an extended warped extra-dimensional model.