Search for Pair Production of Light Scalar Top Quarks inpp¯Collisions ats=1.8TeV

Using $85.2\pm 3.6{\mathrm{p}\mathrm{b}}^{-1}$ of $p\overline{p}$ collisions collected at $\sqrt{s}=1.8\mathrm{T}\mathrm{e}\mathrm{V}$ with the D0 detector at Fermilab’s Tevatron Collider, we present the results of a search for direct pair production of scalar top quarks ($\tilde{t}$), 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 $31.1\pm 6.4$ events from known standard model processes. Comparing these results to next-to-leading-order production cross sections, we exclude a significant region of $\tilde{t}$ and neutralino phase space. In particular, we exclude the $\tilde{t}$ mass $m_{\tilde{t}}<122\mathrm{G}\mathrm{e}\mathrm{V}/c^2$ for a neutralino mass of $45\mathrm{G}\mathrm{e}\mathrm{V}/c^2$.