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

The ATLAS detector at the Large Hadron Collider is used to search for excited electrons and excited muons in the channel pp ????????? ??????????????????* ????????? ????????????????????????, 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?????????*. For m?????????* 0.8 TeV, the respective upper limits on ??????B(?????????* ????????? ???????????????) are 0.75 and 0.90 fb for the e* and ??????* searches. Limits on ??????B are converted into lower bounds on the compositeness scale ??????. In the special case where ?????? = m ?????????*, excited-electron and excited-muon masses below 2.2 TeV are excluded. ?????? CERN 2013.