Search for excited leptons in proton-proton collisions at sqrt(s) = 7 TeV with the ATLAS detector

TL;DR

This paper reports a search for excited leptons in proton-proton collisions at 7 TeV using the ATLAS detector, setting new mass exclusion limits in the absence of evidence.

Contribution

It provides the first limits on excited lepton masses at 7 TeV, excluding masses below 1.87 TeV for electrons and 1.75 TeV for muons when Lambda equals the lepton mass.

Findings

No evidence for excited leptons was observed.

Excluded excited electron masses below 1.87 TeV.

Excluded excited muon masses below 1.75 TeV.

Abstract

The ATLAS detector is used to search for excited leptons in the electromagnetic radiative decay channel l* --> l+gamma. Results are presented based on the analysis of pp collisions at a center-of-mass energy of 7 TeV corresponding to an integrated luminosity of 2.05/fb. No evidence for excited leptons is found, and limits are set on the compositeness scale Lambda as a function of the excited lepton mass m_l*. In the special case where Lambda = m_l*, excited electron and muon masses below 1.87 TeV and 1.75 TeV are excluded at 95% C.L., respectively.