2026/06/18 by CMS Collaboration · 1 voice
Physics and Astronomy · #hep-ex
The first evidence of electroweak (EW) production of pairs of Z bosons in association with two jets (jj) in the final state ZZjj → ℓℓννjj, where ℓ = e, μ, is reported by the CMS experiment. The analysis is based on a data sample of proton-proton (pp) collisions at √(s) = 13 TeV, corresponding to an integrated luminosity of 138 fb-1. Events are selected by requiring exactly two leptons of same flavor and opposite charge, large missing transverse momentum, and two jets with a large rapidity separation and large invariant mass. The EW production cross section in a fiducial volume is σEW(pp → ZZjj → ℓℓννjj) = 0.37+0.14-0.12 (stat)+0.06-0.06 (syst) fb, in agreement with the standard model prediction of 0.39 ± 0.06 fb. The observed (expected) significance of the signal is 3.1 (2.8) standard deviations. Limits on anomalous quartic gauge couplings are derived in terms of dimension-8 effective field theory operators. A combination with the previously reported result from the ZZ decay channel with four charged leptons yields an observed (expected) significance of 5.0 (4.5) standard deviations for the EW production of Z boson pairs.