  A precise measurement of the invisible width of the Z boson produced in
proton-proton collisions at a center-of-mass energy of 13 TeV is presented
using data recorded by the CMS experiment at the LHC, corresponding to an
integrated luminosity of 36.3 fb$^{-1}$. The result is obtained from a
simultaneous fit to kinematic distributions for two data samples of Z boson
plus jets: one dominated by Z boson decays to invisible particles and the other
by Z boson decays to muon and electron pairs. The invisible width is measured
to be 523 $\pm$ 3 (stat) $\pm$ 16 (syst) MeV. This result is the first precise
measurement of the invisible width of the Z boson at a hadron collider, and is
the single most precise direct measurement to date, competitive with the
combined result of the direct measurements from the LEP experiments.
