Search for stopped long-lived particles produced in pp collisions at √ s =7 TeV.

Greg P Heath, Francis J D Bostock, Jim J Brooke, Emyr J Clement, David G Cussans, Henning U Flaecher, Robert J E Frazier, Joel Goldstein, Mark A Grimes, Helen F Heath, Lukasz Kreczko, Simon Metson, David M Newbold, Kachanon Nirunpong, Tony Poll, Sergey Senkin, Vincent J Smith, Tom S Williams, al.) CMS Collaboration (Chatrchyan, S, et

Research output: Contribution to journalArticle (Academic Journal)peer-review

15 Citations (Scopus)


A search has been performed for long-lived particles that have stopped in the CMS detector, during 7 TeV proton-proton operations of the CERN LHC. The existence of such particles could be inferred from observation of their decays when there were no proton-proton collisions in the CMS detector, namely during gaps between LHC beam crossings. Using a data set in which CMS recorded an integrated luminosity of 4.0 inverse femtobarns, and a search interval corresponding to 246 hours of trigger live time, 12 events are observed, with a mean background prediction of 8.6+/-2.4 events. Limits are presented at 95% confidence level on long-lived gluino and stop production, over 13 orders of magnitude of particle lifetime. Assuming the 'cloud model' of R-hadron interactions, a gluino with mass below 640 GeV and a stop with mass below 340 GeV are excluded, for lifetimes between 10 microseconds and 1000 seconds.
Original languageEnglish
Article number26
Pages (from-to)026
Number of pages32
JournalJournal of High Energy Physics
Issue number8
Publication statusPublished - Aug 2012


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