A search for excited leptons in pp collisions at root s=7 TeV

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

PHYSICS LETTERS B, vol.704, no.3, pp.143-162, 2011 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 704 Issue: 3
  • Publication Date: 2011
  • Doi Number: 10.1016/j.physletb.2011.09.021
  • Journal Name: PHYSICS LETTERS B
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.143-162


A search for excited leptons is carried out with the CMS detector at the LHC, using 36 pb(-1) of pp collision data recorded at root s = 7 TeV. The search is performed for associated production of a lepton and an oppositely charged excited lepton pp -> ll*, followed by the decay l* -> l gamma, resulting in the eey final state, where l = e, mu. No excess of events above the standard model expectation is observed. Interpreting the findings in the context of l* production through four-fermion contact interactions and subsequent decay via electroweak processes, first upper limits are reported for l* production at this collision energy. The exclusion region in the compositeness scale A and excited lepton mass M-l* parameter space is extended beyond previously established limits. For Lambda = M-l*, excited lepton masses are excluded below 1070 GeV/c(2) for e* and 1090 GeV/c(2) for mu* at the 95% confidence level. (C) 2011 CERN. Published by Elsevier B.V. All rights reserved.