Search for decays of stopped long-lived particles produced in proton–proton collisions at √s = 8 TeV
Name
Khachatryan-2015-Search for decays of.pdf
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Author(s)
Apyan, Aram
Barbieri, Richard Alexander
Busza, Wit
Cali, Ivan Amos
Di Matteo, Leonardo
Gomez-Ceballos, Guillelmo
Goncharov, Maxim
Gulhan, Doga Can
Klute, Markus
Lai, Yue Shi
Date Issued
April 2015
Journal
The European Physical Journal C
Publisher
Springer-Verlag
Citation
Khachatryan, V., A. M. Sirunyan, A. Tumasyan, W. Adam, T. Bergauer, M. Dragicevic, J. Ero, et al. “Search for Decays of Stopped Long-Lived Particles Produced in Proton–proton Collisions at √s = 8 TeV.” Eur. Phys. J. C 75, no. 4 (April 2015). © 2015 CERN for the benefit of the CMS collaboration
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Final published version
Abstract
A search has been performed for long-lived particles that could have come to rest within the CMS detector, using the time intervals between LHC beam crossings. The existence of such particles could be deduced from observation of their decays via energy deposits in the CMS calorimeter appearing at times that are well separated from any proton–proton collisions. Using a data set corresponding to an integrated luminosity of 18.6 fb[superscript -1] of 8 TeV proton–proton collisions, and a search interval corresponding to 281 h of trigger livetime, 10 events are observed, with a background prediction of 13.2[+3.6 over −2.5] events. Limits are presented at 95% confidence level on gluino and top squark production, for over 13 orders of magnitude in the mean proper lifetime of the stopped particle. Assuming a cloud model of R-hadron interactions, a gluino with mass ≲1000 GeV and a top squark with mass ≲525 GeV are excluded, for lifetimes between 1 μs and 1000s. These results are the most stringent constraints on stopped particles to date.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Laboratory for Nuclear Science
Massachusetts Institute of Technology. School of Science
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DOI of Published Version
https://doi.org/10.1140/epjc/s10052-015-3367-z
