Using Tau Polarization to probe the Stau Co-annihilation Region of mSUGRA Model at LHC

TL;DR

This paper proposes using tau polarization measurements at the LHC to identify the stau co-annihilation region in the mSUGRA model, enabling detection of soft tau signals and precise mass difference measurements.

Contribution

It introduces a novel method leveraging tau polarization to probe the stau co-annihilation region, applicable to a broader class of bino LSP models.

Findings

Tau polarization from stau decay is predicted to be +1 in the co-annihilation region.

The method can extract soft tau signals at the LHC.

It allows measurement of tiny stau-bino mass differences.

Abstract

The mSUGRA model predicts the polarization of the tau coming from the stau to bino decay in the co-annihilation region to be +1. This can be exploited to extract this soft tau signal at LHC and also to measure the tiny mass differences between the stau and the bino LSP. Moreover this strategy will be applicable for a wider class of bino LSP models, where the lighter stau has a right component at least of similar size as the left.