Stau searches and measurements with the ILD concept at the International Linear Collider

TL;DR

This paper evaluates the potential of the International Linear Collider (ILC) to search for and measure the properties of the supersymmetric partner of the tau lepton, focusing on model-independent limits and the impact of tau mixing.

Contribution

It demonstrates the ILC's capability to set model-independent exclusion and discovery limits for tau sleptons, including the worst-case scenario, using full detector simulation.

Findings

ILC can determine tau slepton exclusion/discovery limits independently of model assumptions.

The study identifies the worst-case scenario for tau slepton detection considering mixing effects.

Prospects for measuring tau slepton masses and cross-sections at the ILC are promising.

Abstract

One of the most interesting channels to search for SUSY is the direct pair-production of the $\tau$-lepton superpartner, $\widetilde{\tau}$. The $\widetilde{\tau}$ is with high probability the lightest of the scalar leptons, so one of the first SUSY particles that can be observerd, and the signature of $\widetilde{\tau}$ pair production signal events is one of the most difficult ones, yielding to the ``worst'' and so most global scenario for the searches. Analysis performed at LEP set the current model-independent $\widetilde{\tau}$ limits, suffering from the low energy of this facility. Only under strong model assumptions, these limits are extended to higher masses by LHC studies. In this contribution we show the capability of the ILC, a future electron-positron collider with energy up to 1 TeV, for determining $\widetilde{\tau}$ exclusion/discovery limits in a model-independent way, including an overview of the current state-of-the-art. The determination of the ``worst'' scenario for $\widetilde{\tau}$ exclusion/discovery, taking into account the effect of the $\widetilde{\tau}$ mixing on $\widetilde{\tau}$ production cross-section and efficiency, is also presented. For selected benchmarks, the prospect for measuring masses and polarised cross-sections will be shown. The studies were done studying events passed through the full detector simulation and reconstruction procedures of the International Large Detector (ILD) concept at the ILC. The simulation included all SM backgrounds, as well as the machine induced ones.