Measurement of $ WWZ$ and $ ZH$ Production Cross Sections at $ \sqrt{s}=13$ and 13.6 TeV

A measurement is presented of the cross section in proton-proton collisions for the production of two $ W$ bosons and one $ Z$ boson. It is based on data recorded by the CMS experiment at the CERN LHC at center-of-mass energies $ \sqrt{s}=13$ and 13.6 TeV, corresponding to an integrated luminosity of $ 200\text{}\text{}{\mathrm{fb}}^{-1}$. Events with four charged leptons (electrons or muons) in the final state are selected. Both nonresonant $ WWZ$ production and $ ZH$ production, with the Higgs boson decaying into two $ W$ bosons, are reported. For the first time, the two processes are measured separately in a simultaneous fit. Combining the two modes, signal strengths relative to the standard model (SM) predictions of $ {0.75}_{-0.29}^{+0.34}$ and $ {1.74}_{-0.60}^{+0.71}$ are measured for $ \sqrt{s}=13$ and 13.6 TeV, respectively. The observed (expected) significance for the triboson signal is 3.8 (2.5) standard deviations for $ \sqrt{s}=13.6\text{}\text{}\mathrm{TeV}$, thus providing the first evidence for triboson production at this center-of-mass energy. Combining the two modes and the two center-of-mass energies, the inclusive signal strength relative to the SM prediction is measured to be $ {1.03}_{-0.28}^{+0.31}$, with an observed (expected) significance of 4.5 (5.0) standard deviations.