Searches for Direct Pair Production of Supersymmetric Top and Supersymmetric Bottom Quarks in p-pbar Collisions at sqrt(s)=1.96 TeV

TL;DR

This paper reports a search for supersymmetric top and bottom quarks in proton-antiproton collisions at 1.96 TeV, finding no evidence and setting mass exclusion limits based on the data.

Contribution

First search to set experimental mass limits on supersymmetric top and bottom quarks at Tevatron energies using the CDF II detector.

Findings

No excess events observed over standard model background.

Excluded supersymmetric top quark masses up to 132 GeV/c^2.

Excluded supersymmetric bottom quark masses up to 193 GeV/c^2.

Abstract

We search for direct pair production of supersymmetric top quarks and supersymmetric bottom quarks in proton-antiproton collisions at sqrt(s)=1.96 TeV, using 295 pb^-1 of data recorded by the Collider Detector at Fermilab (CDF II) experiment. The supersymmetric top (supersymmetric bottom) quarks are selected by reconstructing their decay into a charm (bottom) quark and a neutralino, which is assumed to be the lightest supersymmetric particle. The signature of such processes is two energetic heavy-flavor jets and missing transverse energy. The number of events that pass our selection for each search process is consistent with the expected standard model background. By comparing our results to the theoretical production cross sections of the supersymmetric top and supersymmetric bottom quarks in the minimal supersymmetric standard model, we exclude, at a 95% confidence level in the frame of that model, a supersymmetric top quark mass up to 132 GeV/c^2 for a neutralino mass of 48 GeV/c^2, and a supersymmetric bottom quark mass up to 193 GeV/c^2 for a neutralino mass of 40 GeV/c^2.