Search for Pair Production of Light Scalar Top Quarks in p-pbar Collisions at sqrt{s}=1.8 TeV

TL;DR

This paper reports a search for light scalar top quark pair production in proton-antiproton collisions at 1.8 TeV, finding no evidence and setting mass exclusion limits based on observed and expected event counts.

Contribution

It presents the first search for direct pair production of scalar top quarks at the Tevatron with specific event selection criteria and exclusion limits.

Findings

Excluded scalar top quark masses below 122 GeV/c^2 for a 45 GeV/c^2 neutralino.

Observed 27 events against an expectation of 31.1 from standard model.

Set new constraints on supersymmetric particle parameter space.

Abstract

Using 85.2 +/- 3.6 pb^-1 of p-pbar collisions collected at sqrt(s)=1.8 TeV with the D0 detector at Fermilab's Tevatron Collider, we present the results of a search for direct pair production of scalar top quarks ~t, the supersymmetric partners of the top quark. We examined events containing two or more jets and missing transverse energy, the signature of light scalar top quark decays to charm quarks and neutralinos. After selections, we observe 27 events while expecting 31.1 +/- 6.4 events from known standard model processes. Comparing these results to next-to-leading-order production cross sections, we exclude a significant region of ~t and neutralino phase space. In particular, we exclude the ~t mass m_~t < 122 GeV/c^2 for a neutralino mass of 45 GeV/c^2.