Study of the top reconstruction in top-partner events at the LHC
  In the Littlest Higgs model with T-parity (LHT), top-partners (T_-) are produced in pairs at the Large Hadron Collider (LHC). Each top-partner decays into a top quark (t) and the lightest T-odd gauge partner A_H. We demonstrate reconstruction of the ttbar system decaying hadronically, and measurement of the top-partner mass from the m_{T2} distribution. A top quark from a T_{-} decay is polarized, and we discuss the effect of this polarization on the decay distributions. Because the events consist of highly collinear jets which occasionally overlap each other, we compare distributions using different jet reconstruction algorithms (Snowmass cone, kt, Cambridge, SISCone). We find clustering algorithms are advantageous for studying top polarization effects. 
Mihoko M.Nojiri and Michihisa Takeuchi