A search for an excited muon decaying to a muon and two jets in pp collisions at root s=8 TeV with the ATLAS detector

Aad G., Abbott B., Abdallah J., Abdinov O., Abeloos B., Aben R., ...More

NEW JOURNAL OF PHYSICS, vol.18, 2016 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 18
  • Publication Date: 2016
  • Doi Number: 10.1088/1367-2630/18/7/073021
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Keywords: excited leptons, lepton compositeness, leptoquarks, PARTON DISTRIBUTIONS, LEPTON PRODUCTION, CROSS-SECTION, QUARK, HEAVY
  • Gazi University Affiliated: Yes


Anew search signature for excited leptons is explored. Excited muons are sought in the channel pp -> mu mu* -> mu mu jet jet, assuming both the production and decay occur via a contact interaction. The analysis is based on 20.3 fb(-1) of pp collision data at a centre-of-mass energy of root s = 8 TeV taken with the ATLAS detector at the large hadron collider. No evidence of excited muons is found, and limits are set at the 95% confidence level on the cross section times branching ratio as a function of the excited-muon mass m(mu)*. For m(mu)* between 1.3 and 3.0 TeV, the upper limit on sigma B(mu* -> mu q (q) over bar) is between 0.6 and 1 fb. Limits on sB are converted to lower bounds on the compositeness scale Lambda. In the limiting case Lambda = m(mu)*, excited muons with a mass below 2.8 TeV are excluded. With the same model assumptions, these limits at larger mu* masses improve upon previous limits from traditional searches based on the gauge-mediated decay mu* -> mu gamma.