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 36pb−1 of pp collision data recorded at s=7TeV. 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 ⁎Mℓ⁎ parameter space is extended beyond previously established limits. For ⁎Λ=Mℓ⁎, excited lepton masses are excluded below 1070GeV/c2 for ⁎e⁎ and 1090GeV/c2 for ⁎μ⁎ at the 95% confidence level.