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

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 √s = 7 TeV. The search is performed for associated production of a lepton and an oppositely charged excited lepton pp → ∗, followed by the decay ∗ → γ , resulting in the γ final state, where = e,μ. No excess of events above the standard model expectation is observed. Interpreting the findings in the context of ∗ production through four-fermion contact interactions and subsequent decay via electroweak processes, first upper limits are reported for ∗ production at this collision energy. The exclusion region in the compositeness scale Λ and excited lepton mass M∗ parameter space is extended beyond previously established limits. For Λ = M∗ , excited lepton masses are excluded below 1070 GeV/c2 for e∗ and 1090 GeV/c2 for μ∗ at the 95% confidence level.