Combination of searches for high-mass resonances in Zgamma final states in proton-proton collisions at sqrts 8 and 13 TeV

This article describes the search for a high mass scalar particle decaying into a Z boson and a photon. The analysis is performed using proton-proton collision data recorded by the CMS detector at the LHC at a center-of-mass energies of $8~\mathrm{TeV}$ and $13~\mathrm{TeV}$, corresponding to an integrated luminosity of $19.7~\mathrm{fb}^{-1}$ and $2.7~\mathrm{fb}^{-1}$, respectively. 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 and limits at $95\%$ confidence level have been derived on the scalar boson production cross section times the $\mathrm{A}\rightarrow\mathrm{Z}\gamma\rightarrow\ell\ell\gamma$ branching fraction.