# Illuminating Stealth Scenarios at the LHC

## TL;DR

This paper examines how alternative decay channels, including loop-induced and off-shell mediators, can undermine the stealth scenario at the LHC by producing detectable missing energy, especially when these channels have moderate to large branching ratios.

## Contribution

It analyzes the impact of non-two-body decay channels on stealth scenarios, highlighting their significance even at modest branching ratios and their potential to negate stealth signatures.

## Key findings

- Loop-induced and off-shell decay channels can significantly increase MET in stealth scenarios.
- Moderate branching ratios (~10%) into these channels already affect stealth signatures.
- Large branching ratios into photons can fully eliminate stealth advantages.

## Abstract

Several ideas exist how the stringent mass limits from LHC on new coloured particles can be avoided. One idea are the so-called `stealth' scenarios in which missing transversal energy (MET) is avoided due a peculiar mass configuration. It is usually assumed that the cascade decay of the dominantly-produced coloured particle finishes in a two-body decay, where this mass configuration leads to a very small amount of MET. We discuss here the potential impact of other decay channels, either loop-induced or via off-shell mediators. It is shown that those channels already become important even for moderate branching ratios of 10%. Larger branching ratios in particular into a photon can completely wash out all benefits of the stealth setup. We discuss this in a model-independent form, but also at the simplest SUSY stealth scenario which can be realised in the NMSSM.