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

UNSPECIFIED (2016) A search for an excited muon decaying to a muon and two jets in pp collisions at √s=8 TeV with the ATLAS detector. New Journal of Physics, 18 (7): 073021. ISSN 1367-2630

Abstract

A new search signature for excited leptons is explored. Excited muons are sought in the channel pp → μμ∗→ μμ 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 √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 μμ∗. For μμ∗ between 1.3 and 3.0 TeV, the upper limit on φB (μ∗→ μqq) is between 0.6 and 1 fb. Limits on sB are converted to lower bounds on the compositeness scale. In the limiting case L = μμ∗, excited muons with a mass below 2.8 TeV are excluded. With the same model assumptions, these limits at larger μ∗ masses improve upon previous limits from traditional searches based on the gauge-mediated decay μ∗→ μγ.