Search for excited electrons and muons in sqrt(s)=8 TeV proton-proton collisions with the ATLAS detector

Abstract

The ATLAS detector at the LHC is used to search for excited electrons and excited muons in the channel pp -> ll* -> llgamma, assuming that excited leptons are produced via contact interactions. The analysis is based on 13 fb-1 of pp collisions at a centre-of-mass energy of 8 TeV. No evidence for excited leptons is found, and a limit is set at the 95% credibility level on the cross section times branching ratio as a function of the excited-lepton mass m_l*. For m_l* > 0.8 TeV, the respective upper limits on sigma*B(l* -> lgamma) are 0.75 fb and 0.90 fb for the e* and mu* searches. Limits on sigma*B are converted into lower bounds on the compositeness scale Lambda. In the special case where Lambda = m_l*, excited-electron and excited-muon masses below 2.2 TeV are excluded.

15 pages plus author list (39 pages total), 6 figures, 4 tables, submitted to New J. Phys., All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/EXOT-2012-21/

References in corpus (7)

• Parton distributions for the LHC
• New parton distributions for collider physics
• Vector boson pair production at the LHC
• -- HATHOR -- HAdronic Top and Heavy quarks crOss section calculatoR
• Search for excited electrons in ppbar collisions at sqrt(s) = 1.96 TeV
• Search for Excited Muons in ppbar Collisions at sqrt(s) = 1.96 TeV
• Search for excited leptons in e+e- collisions at sqrt{s}=189-209 GeV

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