Search for the Production of a Long-Lived Neutral Particle Decaying within the ATLAS Hadronic Calorimeter in Association with a Z Boson from pp Collisions at root s=13 TeV

M. Aaboud, G. Aad, B. Abbott, O. Abdinov, B Abeloos, DK Abhayasinghe, S.H. Abidi, Ossama Sherif Alexander Abouzeid, NL Abraham, H. Abramowicz, H. Abreu, Y. Abulaiti, B.S. Acharya, Sosuke Adachi, Luise Adam, L. Adamczyk, J. Adelman, M. Adersberger, A. Adiguzel, T. AdyeA. A. Affolder, Y. Afik, C. Agheorghiesei, J. A. Aguilar-Saavedra, F. Ahmadov, Mogens Dam, Simon Holm Stark, Flavia de Almeida Dias, Alejandro Alonso Diaz, Gorm Aske Gram Krohn Galster, Geert-Jan Besjes, Jørgen Beck Hansen, Milena Bajic, hqz214 hqz214, Jørn Dines Hansen, Peter Henrik Hansen, Troels Christian Petersen, Graig Wiglesworth, James William Monk, Stefania Xella, The ATLAS collaboration

28 Citations (Scopus)
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Abstract

This Letter presents a search for the production of a long-lived neutral particle (Zd) decaying within the ATLAS hadronic calorimeter, in association with a standard model (SM) Z boson produced via an intermediate scalar boson, where Z→+ (=e, μ). The data used were collected by the ATLAS detector during 2015 and 2016 pp collisions with a center-of-mass energy of s=13 TeV at the Large Hadron Collider and correspond to an integrated luminosity of 36.1±0.8 fb-1. No significant excess of events is observed above the expected background. Limits on the production cross section of the scalar boson times its decay branching fraction into the long-lived neutral particle are derived as a function of the mass of the intermediate scalar boson, the mass of the long-lived neutral particle, and its cτ from a few centimeters to one hundred meters. In the case that the intermediate scalar boson is the SM Higgs boson, its decay branching fraction to a long-lived neutral particle with a cτ approximately between 0.1 and 7 m is excluded with a 95% confidence level up to 10% for mZd between 5 and 15 GeV.

Original languageEnglish
Article number151801
JournalPhysical Review Letters
Volume122
Issue number15
ISSN0031-9007
DOIs
Publication statusPublished - 15 Apr 2019

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