PT Journal
AU ATLAS Collaboration (Aad, Gea
   Aparisi Pozo, JA
   Bailey, AJ
   Cabrera Urban, S
   Cardillo, F
   Castillo Gimenez, V
   Costa, MJ
   Didenko
   Escobar, C
   Estrada Pastor, O
   Fiorini, L
   Fullana Torregrosa, E
   Fuster, J
   Garcia, C
   Garcia Navarro, JE
   Gonzalez de la Hoz, S
   Gonzalvo Rodriguez, GR
   Guerrero Rojas, JGR
   Higon-Rodriguez, E
   Lacasta, C
   Lozano Bahilo, JJ
   Mamuzic, J
   Marti-Garcia, S
   Martinez Agullo, P
   Miralles Lopez, M
   Mitsou, VA
   Monsonis Romero, L
   Moreno Llacer, M
   Navarro-Gonzalez, J
   Poveda, J
   Prades Ibañez, A
   Ruiz-Martinez, A
   Sabatini, P
   Salt, J
   Sanchez Sebastian, V
   Sayago Galvan, I
   Soldevila, U
   Sanchez, J
   Torro Pastor, E
   Valero, A
   Valls Ferrer, JA
   Villaplana Perez, M
   Vos, M
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
SO European Physical Journal C
JI Eur. Phys. J. C
PY 2022
BP 105
EP 41pp
VL 82
IS 2
DI 10.1140/epjc/s10052-021-09878-z
LA English
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.
ER