  This paper describes the search for a high-mass narrow-width scalar particle
decaying into a Z boson and a photon. The analysis is performed using
proton-proton collision data recorded with the CMS detector at the LHC at
center-of-mass energies of 8 and 13 TeV, corresponding to integrated
luminosities of 19.7 and 2.7 inverse femtobarns, respectively. The Z bosons are
reconstructed from opposite-sign electron or muon pairs. No statistically
significant deviation from the standard model predictions has been found in the
200-2000 GeV mass range. Upper limits at 95% confidence level have been derived
on the product of the scalar particle production cross section and the
branching fraction of the Z decaying into electrons or muons, which range from
280 to 20 fb for resonance masses between 200 and 2000 GeV.
