Aad, G.Abbott, B.Abbott, D.C.Abud, A. AbedAbeling, K.Abhayasinghe, D.K.Abidi, S.H.Aboulhorma, A.Abramowicz, H.Abreu, H.Abulaiti, Y.Hoffman, A. C. AbuslemeAcharya, B.S.Achkar, B.Adam, L.Bourdarios, C. AdamAdamczyk, L.Adamek, L.Addepalli, S.V.Adelman, J.Adiguzel, A.Adorni, S.Adye, T.Affolder, A.A.Afik, Y.Agapopoulou, C.Agaras, M.N.Agarwala, J.Aggarwal, A.Agheorghiesei, C.Aguilar-Saavedra, J.A.Ahmad, A.Ahmadov, F.Ahmed, W.S.Ai, X.Aielli, G.Aizenberg, I.Akatsuka, S.Akbiyik, M.Åkesson, T.P.A.Akimov, A.V.Khoury, K. AlAlberghi, G.L.Albert, J.Albicocco, P.Verzini, M. J. AlconadaAlderweireldt, S.Aleksa, M.Aleksandrov, I.N.Alexa, C.Alexopoulos, T.Alfonsi, A.Alfonsi, F.Alhroob, M.Ali, B.Ali, S.Aliev, M.Alimonti, G.Allaire, C.Allbrooke, B.M.M.2024-07-302024-07-302022-02European Physical Journal C, Volume 82, Issue 2, February 2022, Article number 1051434-6044https://repositorio.unab.cl/handle/ria/58867Indexación: Scopus.This paper presents a measurement of the electroweak production of two jets in association with a Zγ pair, with the Z boson decaying into two neutrinos. It also presents a search for invisible or partially invisible decays of a Higgs boson with a mass of 125 GeV produced through vector-boson fusion with a photon in the final state. These results use data from LHC proton–proton collisions at s = 13 TeV collected with the ATLAS detector and corresponding to an integrated luminosity of 139 fb - 1. The event signature, shared by all benchmark processes considered for the measurements and searches, is characterized by a significant amount of unbalanced transverse momentum and a photon in the final state, in addition to a pair of forward jets. Electroweak Zγ production in association with two jets is observed in this final state with a significance of 5.2 (5.1 expected) standard deviations. The measured fiducial cross-section for this process is 1.31 ± 0.29 fb. An observed (expected) upper limit of 0.37 (0.34-0.10+0.15) at 95% confidence level is set on the branching ratio of a 125 GeV Higgs boson to invisible particles, assuming the Standard Model production cross-section. The signature is also interpreted in the context of decays of a Higgs boson into a photon and a dark photon. An observed (expected) 95% CL upper limit on the branching ratio for this decay is set at 0.018 (0.017-0.005+0.007), assuming the Standard Model production cross-section for a 125 GeV Higgs boson. © 2022, The Author(s).enHadronLeptonStandard ModelArtículoAttribution 4.0 International CC BY 4.0 Deed10.1140/epjc/s10052-021-09878-z