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) = 0.37-0.12+0.14(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.
Observation of Electroweak Production of Pairs of Z Bosons in Proton-Proton Collisions at 13 TeV
Abbrescia, M.;Buonsante, M.;Colaleo, A.;De Palma, M.;Elmetenawee, W.;Generoso, L.;Louka, M.;My, S.;Nenna, F.;Nuzzo, S.;Pellecchia, A.;Pompili, A.;Radogna, R.;Simone, F. M.;Stamerra, A.;Troiano, D.;Venditti, R.;Zaza, A.;D'Anzi, B.;
2026-01-01
Abstract
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) = 0.37-0.12+0.14(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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.


