Search for light long-lived neutral particles produced in pp collisions at √s=13TeV and decaying into collimated leptons or light hadrons with the ATLAS detector

Summary, in English

Several models of physics beyond the Standard Model predict the existence of dark photons, light neutral particles decaying into collimated leptons or light hadrons. This paper presents a search for long-lived dark photons produced from the decay of a Higgs boson or a heavy scalar boson and decaying into displaced collimated Standard Model fermions. The search uses data corresponding to an integrated luminosity of 36.1 fb- 1 collected in proton–proton collisions at s=13 Te recorded in 2015–2016 with the ATLAS detector at the Large Hadron Collider. The observed number of events is consistent with the expected background, and limits on the production cross section times branching fraction as a function of the proper decay length of the dark photon are reported. A cross section times branching fraction above 4 pb is excluded for a Higgs boson decaying into two dark photons for dark-photon decay lengths between 1.5 mm and 307 mm.

• Author: G Aad; Torsten Åkesson; Simona Bocchetta; Lene Bryngemark; Eric Edward Corrigan; Caterina Doglioni; Kristian Gregersen; Eva Brottmann Hansen; Vincent Hedberg; Göran Jarlskog; Charles Kalderon; Edgar Kellermann; Balazs Konya; Else Lytken; Katja Mankinen; Caterina Marcon; Ulf Mjörnmark; Geoffrey André Adrien Mullier; Ruth Pöttgen; Trine Poulsen; Eleni Skorda; Oxana Smirnova; L. Zwalinski
• Department/s: Particle and nuclear physics; eSSENCE: The e-Science Collaboration
• Publishing year: 2020-05-20
• Language: English
• Publication/Series: European Physical Journal C
• Volume: 80
• Issue: 5
• Links: http://dx.doi.org/10.1140/epjc/s10052-020-7997-4
• Document type: Journal article
• Publisher: Springer
• Topic: Subatomic Physics
• Status: Published
• ISBN/ISSN/Other: ISSN: 1434-6044