Search for Pair Production of Supersymmetric Top Quarks in Dilepton Events from $p\bar{p}$ Collisions at $\sqrt{s}$ = 1.96 TeV

TL;DR

This paper reports a search for supersymmetric top quark pair production in dilepton events from proton-antiproton collisions, finding no evidence and setting mass limits on the particles involved.

Contribution

First search for stop quark pair production in dilepton events at Tevatron, establishing new mass exclusion limits for supersymmetric particles.

Findings

No evidence for stop pair production was observed.

Set 95% confidence level limits on stop and neutralino masses.

Analyzed 2.7 fb$^{-1}$ of collision data with the CDF II detector.

Abstract

We present the results of a search for pair production of the supersymmetric partner of the top quark (the stop quark $\tilde{t}_{1}$) decaying to a $b$-quark and a chargino $\chargino$ with a subsequent $\chargino$ decay into a neutralino $\neutralino$, lepton $\ell$, and neutrino $\nu$. Using a data sample corresponding to 2.7 fb$^{-1}$ of integrated luminosity of $p\bar{p}$ collisions at $\sqrt{s} = 1.96$ TeV collected by the CDF II detector, we reconstruct the mass of candidate stop events and fit the observed mass spectrum to a combination of standard model processes and stop quark signal. We find no evidence for $\pairstop$ production and set 95% C.L. limits on the masses of the stop quark and the neutralino for several values of the chargino mass and the branching ratio ${\cal B}(\chargino\to\neutralino\ell^{\pm}\nu)$.