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

Abstract

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→ℓℓ^*, followed by the decay ℓ^*→ℓγ, resulting in the ℓℓγ final state, where ℓ=e,μ. 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 Λ and excited lepton mass M_(ℓ*) parameter space is extended beyond previously established limits. For Λ=M_(ℓ*), excited lepton masses are excluded below 1070 GeV/c^2 for e^* and 1090 GeV/c^2 for μ^* at the 95% confidence level.

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