Search for Excited and Exotic Muons in the mu+gamma Decay Channel in   p-pbar Collisions at sqrt{s} = 1.96 TeV
  We present a search for excited and exotic muon states mu*, conducted using an integrated luminosity of 371 pb^{-1} of data collected in p-pbar collisions at sqrt{s} = 1.96 TeV at the Tevatron with the CDF II detector. We search for associated production of mu+mu* followed by the decay mu* -> mu+gamma, resulting in the mu+mu+gamma final state. We compare the data to model predictions as a function of the mass of the excited muon M(mu*), the compositeness energy scale Lambda, and the gauge coupling factor f. No signal above the standard model expectation is observed in the mu+gamma mass spectrum. In the contact interaction model, we exclude 107 < M(mu*) < 853 GeV/c^2 for Lambda = M(mu*); in the gauge-mediated model, we exclude 100 < M(mu) < 410 GeV/c^2 for f/Lambda = 0.01/GeV. These 95% confidence level exclusions extend previous limits and are the first hadron collider results on mu* production in the gauge-mediated model. 
CDF Collaboration: A. Abulencia, et al