TY - JOUR AU - ATLAS Collaboration (Aad, G. et al AU - Aparisi Pozo, J. A. AU - Bailey, A. J. AU - Cabrera Urban, S. AU - Cardillo, F. AU - Castillo Gimenez, V. AU - Costa, M. J. AU - Didenko AU - Escobar, C. AU - Estrada Pastor, O. AU - Fiorini, L. AU - Fullana Torregrosa, E. AU - Fuster, J. AU - Garcia, C. AU - Garcia Navarro, J. E. AU - Gonzalez de la Hoz, S. AU - Gonzalvo Rodriguez, G. R. AU - Guerrero Rojas, J. G. R. AU - Higon-Rodriguez, E. AU - Lacasta, C. AU - Lozano Bahilo, J. J. AU - Mamuzic, J. AU - Marti-Garcia, S. AU - Martinez Agullo, P. AU - Miralles Lopez, M. AU - Mitsou, V. A. AU - Monsonis Romero, L. AU - Moreno Llacer, M. AU - Navarro-Gonzalez, J. AU - Poveda, J. AU - Prades IbaƱez, A. AU - Ruiz-Martinez, A. AU - Sabatini, P. AU - Salt, J. AU - Sanchez Sebastian, V. AU - Sayago Galvan, I. AU - Soldevila, U. AU - Sanchez, J. AU - Torro Pastor, E. AU - Valero, A. AU - Valls Ferrer, J. A. AU - Villaplana Perez, M. AU - Vos, M. PY - 2022 DA - 2022// TI - 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 T2 - Eur. Phys. J. C JO - European Physical Journal C SP - 105 EP - 41pp VL - 82 IS - 2 PB - Springer AB - 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. SN - 1434-6044 UR - https://arxiv.org/abs/2109.00925 UR - https://doi.org/10.1140/epjc/s10052-021-09878-z DO - 10.1140/epjc/s10052-021-09878-z LA - English N1 - WOS:000751762900004 ID - ATLASCollaborationAad_etal2022 ER -