Search for dark matter particles produced in $\mathrm{W}^{+}\mathrm{W}^{-}$ events with transverse momentum imbalance in proton-proton collisions at $\sqrt{s}=13~\mathrm{TeV}$ with the CMS detector

A search for dark matter particles is performed using events with a pair of $\mathrm{W}$ bosons and large missing transverse momentum. Candidates are selected by requiring one or two leptons (electrons or muons) from the $\mathrm{W}$ boson decays. The analysis is based on proton-proton collision data taken at a center-of-mass energy of 13 TeV by the CMS experiment at the LHC and corresponding to an integrated luminosity of $137~\mathrm{fb}^{-1}$. No significant excess over the expected standard model background is observed in the semi- and di-leptonic final states of the $\mathrm{W}^{+}\mathrm{W}^{-}$ decay channel. Limits are set on dark matter production in the context of a dark Higgs simplified model, with a dark Higgs mass above the $\mathrm{W}^{+}\mathrm{W}^{-}$ mass threshold.