Search for Excited and Exotic Muons in the mu+gamma Decay Channel in p-pbar Collisions at sqrt{s} = 1.96 TeV

TL;DR

This paper reports a search for excited and exotic muon states in proton-antiproton collisions at 1.96 TeV, finding no evidence of such particles and setting new exclusion limits on their masses and couplings.

Contribution

First hadron collider search for mu* in gauge-mediated models, extending previous limits and exploring new parameter space.

Findings

Excluded mu* masses between 107 and 853 GeV/c^2 for Lambda = M(mu*)

Excluded mu* masses between 100 and 410 GeV/c^2 for f/Lambda = 0.01/GeV

No significant excess observed in the mu+gamma spectrum

Abstract

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.