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


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Chatrchyan S., Khachatryan V., Sirunyan A., Tumasyan A., Adam W., Bergauer T., ...More

JOURNAL OF HIGH ENERGY PHYSICS, no.8, 2012 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: Issue: 8
  • Publication Date: 2012
  • Doi Number: 10.1007/jhep08(2012)026
  • Journal Name: JOURNAL OF HIGH ENERGY PHYSICS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Keywords: Hadron-Hadron Scattering, CHARGED-PARTICLES, GLUINO PRODUCTION, SQUARK, DECAYS
  • Çukurova University Affiliated: Yes

Abstract

A search has been performed for long-lived particles that have stopped in the CMS detector, during 7TeV 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 fb(-1), 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 mu s and 1000s.