@Article{ATLASCollaborationAad_etal2023, author="ATLAS Collaboration (Aad, G. et al and Amos, K. R. 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 Fiorini, L. and Fullana Torregrosa, E. and Fuster, J. and Garcia, C. and Garcia Navarro, J. E. and Gomez Delegido, A. J. 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="Search for light long-lived neutral particles that decay to collimated pairs of leptons or light hadrons in pp collisions at root s=13 TeV with the ATLAS detector", journal="Journal of High Energy Physics", year="2023", publisher="Springer", volume="06", number="6", pages="153--55pp", optkeywords="Exotics; Hadron-Hadron Scattering", abstract="A search for light long-lived neutral particles with masses in the O(MeV-GeV) range is presented. The analysis targets the production of long-lived dark photons in the decay of a Higgs boson produced via gluon-gluon fusion or in association with a W boson. Events that contain displaced collimated Standard Model fermions reconstructed in the calorimeter or muon spectrometer are selected in 139 fb(-1) of p s = 13TeV pp collision data collected by the ATLAS detector at the LHC. Background estimates for contributions from Standard Model processes and instrumental effects are extracted from data. The observed event yields are consistent with the expected background. Exclusion limits are reported on the production cross-section times branching fraction as a function of the mean proper decay length c tau of the dark photon, or as a function of the dark-photon mass and kinetic mixing parameter that quantifies the coupling between the Standard Model and potential hidden (dark) sectors. A Higgs boson branching fraction above 1{\%} is excluded at 95{\%} CL for a Higgs boson decaying into two dark photons for dark-photon mean proper decay lengths between 10 mm and 250 mm and dark photons with masses between 0.4 GeV and 2 GeV.", optnote="WOS:001035251600001", optnote="exported from refbase (https://references.ific.uv.es/refbase/show.php?record=5653), last updated on Sun, 17 Sep 2023 19:01:07 +0000", issn="1029-8479", doi="10.1007/JHEP06(2023)153", opturl="https://arxiv.org/abs/2206.12181", opturl="https://doi.org/10.1007/JHEP06(2023)153", language="English" }