Search for Pair Production of Supersymmetric Top Quarks in Dilepton Events from pp̅ Collisions at √s=1.96 TeV

Abstract

We present the results of a search for pair production of the supersymmetric partner of the top quark (the top squark t˜1) decaying to a b quark and a chargino χ˜1± with a subsequent χ˜1± decay into a neutralino χ˜10, lepton ℓ, and neutrino ν. Using a data sample corresponding to 2.7 fb-1 of integrated luminosity of pp̅ collisions at √s=1.96 TeV collected by the CDF II detector, we reconstruct the mass of top squark candidate events and fit the observed mass spectrum to a combination of standard model processes and t˜1t˜̅ 1 signal. We find no evidence for t˜1t˜̅ 1 production and set 95% C.L. limits on the masses of the top squark and the neutralino for several values of the chargino mass and the branching ratio B(χ˜1±→χ˜10ℓ±ν).