A search for excited leptons, carried out with the CMS detector in pp collision at the LHC with vs = 7 TeV, is presented. The search has been performed for an associated production of a lepton and an oppositely charged excited lepton pp → ll*, followed by the decay l* → lγ , resulting in llγ final state, where l = e,μ. No excess above the Standard Model expectation is observed in the data. Interpreting the findings in the context of l* production through four-fermion contact interactions and l* decay via electroweak processes, upper limits are reported for l* production at this collision energy and the exclusion region in the δ - M(l*) parameter space is extended beyond the previously established limits.
Bibliographical noteFunding Information:
We congratulate our colleagues in the CERN accelerator departments for the excellent performance of the LHC machine. We thank the technical and administrative staff at CERN and other CMS institutes, and acknowledge support from: FMSR (Austria); FNRS and FWO (Belgium); CNPq , CAPES , FAPERJ , and FAPESP (Brazil); MES (Bulgaria); CERN ; CAS , MoST , and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF (Cyprus); MoER , SF0690030s09 and ERDF (Estonia); Academy of Finland , MEC , and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF , DFG , and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); I± (Iran); SFI (Ireland); INFN (Italy); NRF and WCU (Republic of Korea); LAS (Lithuania); CINVESTAV , CONACYT , SEP , and UASLP-FAI (Mexico); MSI (New Zealand); PAEC (Pakistan); MSHE and NSC (Poland); FCT (Portugal); JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MON , RosAtom , RAS and RFBR (Russia); MSTD (Serbia); MICINN and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey); STFC (United Kingdom); DOE and NSF (USA). Individuals have received support from the Marie-Curie programme and the European Research Council (European Union); the Leventis Foundation ; the A.P. Sloan Foundation ; the Alexander von Humboldt Foundation ; the Belgian Federal Science Policy Office ; the Fonds pour la Formation à la Recherche dans lʼIndustrie et dans lʼAgriculture (FRIA-Belgium); the Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium); the Council of Scientific and Industrial Research , India; and the HOMING PLUS programme of Foundation for Polish Science , cofinanced from European Union, Regional Development Fund .
- Compact muon solenoid
- Contact interaction
- Excited leptons
- Large hadron collider