Search for dark matter produced in association with a leptonically decaying Z boson in proton-proton collisions at √s=13TeV

A search for dark matter particles is performed using events with a Z boson candidate and large missing transverse momentum. The analysis is based on proton-proton collision data at a center-of-mass energy of 13 TeV, collected by the CMS experiment at the LHC in 2016-2018, corresponding to an integrated luminosity of 137 fb(-1). The search uses the decay channels Z -> ee and Z -> mu mu. No significant excess of events is observed over the background expected from the standard model. Limits are set on dark matter particle production in the context of simplified models with vector, axial-vector, scalar, and pseudoscalar mediators, as well as on a two-Higgs-doublet model with an additional pseudoscalar mediator. In addition, limits are provided for spin-dependent and spin-independent scattering cross sections and are compared to those from direct-detection experiments. The results are also interpreted in the context ofmodels of invisible Higgs boson decays, unparticles, and large extra dimensions.

Automated summary

A search for dark matter particles was conducted using events with a Z boson candidate and large missing transverse momentum at a center-of-mass energy of 13 TeV, based on data from proton-proton collisions collected by the CMS experiment at the LHC from 2016 to 2018. No significant event excess was observed over the expected background from the standard model. Limits were set on dark matter particle production in various simplified models and a two-Higgs-doublet model, with comparisons to direct-detection experiments for scattering cross sections.