@Article{ATLASCollaborationAad_etal2022, author="ATLAS Collaboration (Aad, G. et al and Aparisi Pozo, J. A. and Bailey, A. J. and Cabrera Urban, S. and Cardillo, F. and Castillo Gimenez, V. and Costa, M. J. and Didenko and Escobar, C. and Estrada Pastor, O. and Fiorini, L. and Fullana Torregrosa, E. and Fuster, J. and Garcia, C. and Garcia Navarro, J. E. and Gonzalez de la Hoz, S. and Gonzalvo Rodriguez, G. R. and Guerrero Rojas, J. G. R. and Higon-Rodriguez, E. and Lacasta, C. and Lozano Bahilo, J. J. and Mamuzic, J. and Marti-Garcia, S. and Martinez Agullo, P. and Miralles Lopez, M. and Mitsou, V. A. and Monsonis Romero, L. and Moreno Llacer, M. and Navarro-Gonzalez, J. and Poveda, J. and Prades Iba{\~{n}}ez, A. and Ruiz-Martinez, A. and Sabatini, P. and Salt, J. and Sanchez Sebastian, V. and Sayago Galvan, I. and Soldevila, U. and Sanchez, J. and Torro Pastor, E. and Valero, A. and Valls Ferrer, J. A. and Villaplana Perez, M. and Vos, M.", title="Observation of electroweak production of two jets in association with an isolated photon and missing transverse momentum, and search for a Higgs boson decaying into invisible particles at 13 TeV with the ATLAS detector", journal="European Physical Journal C", year="2022", publisher="Springer", volume="82", number="2", pages="105--41pp", abstract="This paper presents a measurement of the electroweak production of two jets in association with a Z gamma 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 vectorboson fusion with a photon in the final state. These results use data from LHC proton-proton collisions at root s = 13 TeV collected with the ATLAS detector and corresponding to an integated 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 Z gamma 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.", optnote="WOS:000751762900004", optnote="exported from refbase (https://references.ific.uv.es/refbase/show.php?record=5113), last updated on Fri, 18 Feb 2022 08:30:17 +0000", issn="1434-6044", doi="10.1140/epjc/s10052-021-09878-z", opturl="https://arxiv.org/abs/2109.00925", opturl="https://doi.org/10.1140/epjc/s10052-021-09878-z", language="English" }