Search for Associated Chargino-Neutralino Production in Final States with Two Muons and an Additional Lepton

We present a search for chargino-neutralino production based on approximately 300 pb$^{-1}$ of Tevatron Run II data collected in proton anti-proton collisions at $\sqrt{s}$ = $1.96$ TeV with the Collider Detector at Fermilab (CDF). We perform a blind analysis and we check our predictions of the Standard Model backgrounds in control regions before analyzing the signal region. The results presented here are obtained in events where we firstly identify two muons and then select an additional electron or muon as third lepton. The data are used to constrain the SUSY parameter space.