Search for a new heavy scalar resonance decaying to a pair of Z bosons in the four-lepton final state in proton-proton collisions at $ \sqrt{s}=13 $ TeV

A search for a new heavy scalar resonance decaying to two Z bosons, each subsequently decaying to a pair of electrons or muons, is presented. The results are based on a proton-proton collision data set collected by the CMS experiment at the LHC at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb$^{−1}$. The search is performed over a wide range of resonance masses from 130 GeV to 3 TeV, considering both narrow- and broad-width scenarios, and considering the gluon fusion and vector boson fusion production processes. For the broad-width scenario, the interference between the new resonance, the 125 GeV Higgs boson production, and the continuum background is taken into account. No significant excess with respect to the standard model background expectation is observed in the examined phase space. Upper limits at the 95% confidence level are set on the product of the heavy scalar resonance production cross section and the branching fraction for its decay into two Z bosons. The exclusion limits range from 0.05–0.1 pb in the low-mass region to 0.005 pb in the high-mass region.