Precision Measurements in the Scalar Top Sector of the MSSM at a Linear e+e- Collider

TL;DR

This study assesses the precision of scalar top measurements in the MSSM at a future linear collider, emphasizing the importance of beam polarization and providing detailed estimates of mass and mixing angle uncertainties.

Contribution

It provides detailed simulation-based estimates of scalar top mass and mixing angle measurement precisions at a linear collider, including the impact of beam polarization and c-tagging.

Findings

Mass measurement uncertainty of 0.5-0.8 GeV

Mixing angle uncertainty of 0.004-0.0125

Beam polarization significantly improves sensitivity

Abstract

The scalar top discovery potential has been studied for the TESLA project with a full-statistics background simulation at sqrt(s)=500 GeV and L=500 fb-1. 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(cos(Theta))=0.008 in the neutralino channel, and Delta(m)=0.5 GeV and Delta(cos(Theta))=0.004 in the chargino channel. The MSSM parameters for the Snowmass point 5 at cos(Theta)=0.513 predict a scalar top of 210 GeV and a neutralino of about 120 GeV. For this parameter choice Delta(m)=0.95 GeV and Delta(cos(Theta))=0.0125 is obtained, and a preliminary c-tagging study is presented in the neutralino channel.