  The scalar top discovery potential has been studied with a full-statistics
background simulation at sqrt(s)=500 GeV and L = 500 fb-1 for the TESLA
project. The beam polarization is very important to measure the scalar top
mixing angle and to determine its mass. The latest estimation of the beam
polarization parameters is applied. This study includes e+ polarization, which
improves the sensitivity. For a 180 GeV scalar top at minimum production cross
section, we obtain delta(m) = 0.8 GeV and delta(cosT) = 0.008 in the neutralino
decay channel, and delta(m) = 0.5 GeV and delta(cosT) = 0.004 in the chargino
decay channel.
