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 Λ 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/c² for e^· and 1090 GeV/c² for μ^· at the 95% confidence level.