Analyzing polarized boosted top from stop decay at high luminosity and high energy LHC

Abstract

Measuring top polarization is extremely important in understanding any new physics that couples to top quark. Here, we take up the task of extracting polarization of top quark coming from TeV-scale stop decay at the upgraded high luminosity and high energy LHC. We focus on the scenario where the two tops from the stop decay lead to semi-leptonic final state. We take into account all relevant backgrounds and put kinematical cuts to suppress them. We arrive at a signal region where the desired signal can be observed with reasonable significance. Next, we examine, in such signal regions, how well top polarization can be measured. For that we have calculated the degree with which left- and right-handed top quarks can be separated from each other, in terms of $P$-values. We have also performed a comparative study between various centre-of-mass energies and integrated luminosities in terms of their reach in probing top polarization from stop decay.