Search for the production of WWW events with two equally charged or three leptons at sqrt(s) = 13 TeV

A search for the production of events containing three W bosons is reported. The search is based on a data sample of proton-proton collisions at $\sqrt{s}=13\,\mathrm{TeV}$ recorded by the CMS experiment and corresponding to a total integrated luminosity of $35.9\,\mathrm{fb}^{-1}$. The search is performed in final states with two leptons (electrons or muons) of the same charge or with three leptons. The observed (expected) significance for WWW production is $0.60~(1.78)$ standard deviations, and the ratio of measured signal yields to that expected from the standard model is $0.34^{+0.62}_{-0.34}$. Limits are also placed on anomalous quartic gauge couplings and on the production of massive axion-like particles.