Search for Pair Production of Light Scalar Top Quarks in p-pbar   Collisions at sqrt{s}=1.8 TeV
  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. 
Carl Lundstedt, Dan Claes (for the D0 Collaboration)