Top quark mass measurements at and above threshold at CLIC

TL;DR

This paper evaluates the expected precision of top quark mass measurements at a CLIC-based linear e+ e- collider, using simulation and two measurement techniques, achieving about 100 MeV accuracy.

Contribution

It provides a detailed simulation-based analysis of top mass measurement methods at CLIC, including systematic uncertainties and comparison with ILC.

Findings

Experimental uncertainties around 100 MeV for direct reconstruction.

Total uncertainties around 100 MeV for threshold scan.

Comparable precision levels for CLIC and ILC in top mass measurement.

Abstract

We present a study of the expected precision of the top quark mass determination, measured at a linear e+ e- collider based on CLIC technology. GEANT4-based detector simulation and full event reconstruction including realistic physics and beam-induced background levels are used. Two different techniques to measure the top mass are studied: The direct reconstruction of the invariant mass of the top quark decay products and the measurement of the mass together with the strong coupling constant in a threshold scan, in both cases including first studies of expected systematic uncertainties. For the direct reconstruction, experimental uncertainties around 100 MeV are achieved, which are at present not matched by a theoretical understanding on a similar level. With a threshold scan, total uncertainties of around 100 MeV are achieved, including theoretical uncertainties in a well-defined top mass scheme. For the threshold scan, the precision at ILC is also studied to provide a comparison of the two linear collider technologies.