ATLAS, Collaboration; Agustoni, Marco; Ancu, Lucian; Battaglia, Andreas; Beck, Hans Peter; Borer, Claudia; Cervelli, Alberto; Ereditato, Antonio; Gallo, Valentina; Haug, Sigve; Kabana, Sonja; Kruker, Tobias; Marti, Lukas; Pretzl, Klaus-Peter; Schneider, Basil; Sciacca, Gianfranco; Stucci, Stefania Antonia; Weber, Michael (2013). Search for excited electrons and muons in sqrts=8 TeV proton-proton collisions with the ATLAS detector. New journal of physics, 15(9), 093011. Institute of Physics Publishing IOP 10.1088/1367-2630/15/9/093011
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1367-2630_15_9_093011.pdf - Published Version Available under License Creative Commons: Attribution (CC-BY). Download (689kB) | Preview |
The ATLAS detector at the Large Hadron Collider is used to search for excited electrons and excited muons in the channel pp -> ll* -> ll gamma, 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(l*). For m(l*) >= 0.8 TeV, the respective upper limits on sigma B(l(*) -> l gamma) are 0.75 and 0.90 fb for the e* and mu* searches. Limits on sigma B are converted into lower bounds on the compositeness scale 3. In the special case where Lambda = m(l*), excited-electron and excited-muon masses below 2.2 TeV are excluded.