Search for direct pair production of scalar top quarks in the single- and dilepton channels in proton-proton collisions at sqrt(s) = 8 TeV

TL;DR

This paper reports a search for scalar top quarks in proton-proton collisions at 8 TeV using CMS data, finding no significant excess and setting exclusion limits on their masses.

Contribution

It presents the first search for top squark pair production in single- and dilepton channels at 8 TeV with CMS, excluding certain mass regions.

Findings

No significant excess observed over standard model background.

Excluded top squark masses up to about 700 GeV.

Excluded neutralino masses up to about 250 GeV.

Abstract

Results are reported from a search for the top squark, the lighter of the two supersymmetric partners of the top quark. The data sample corresponds to 19.7 inverse femtobarns of proton-proton collisions at sqrt(s) = 8 TeV collected with the CMS detector at the LHC. The search targets top squark to b chi+/- and top squark to t(*) chi0 decay modes, where chi+/- and chi0 are the lightest chargino and neutralino, respectively. The reconstructed final state consists of jets, b jets, missing transverse energy, and either one or two leptons. Leading backgrounds are determined from data. No significant excess in data is observed above the expectation from standard model processes. The results exclude a region of the two-dimensional plane of possible top squark and chi0 masses. The highest excluded top squark and chi0 masses are about 700 GeV and 250 GeV, respectively.