Study of scalar top quarks in the neutralino and chargino decay channel at a future e+e? linear collider

Abstract

The scalar top discovery potential has been studied with a full-statistics background simulation for √s = 500GeV and \({\cal L}\) = 500fb−1. The simulation is based on a fast and realistic simulation of a TESLA detector. The large simulated data sample allowed the application of an Iterative Discriminant Analysis (IDA) which led to a significantly higher sensitivity than in previous studies. The effects of beam polarization on signal efficiency and individual background channels are studied using separate optimization with the IDA for both polarization states. The beam polarization is very important to measure the scalar top mixing angle and to determine its mass. Simulating a 180 GeV scalar top at minimum production cross section, we obtain Δm = 1GeV and Δcos\(\theta_{\tilde t}\) = 0.009 in the neutralino decay channel, and Δm = 0.5 GeV and Δcos\(\theta{\tilde t}\) = 0.004 in the chargino decay channel.