Naughty or Nice? The Role of the `N' in the Natural NMSSM for the LHC

TL;DR

This paper investigates mass limits on gluinos and stops within a natural NMSSM framework featuring a singlino LSP, analyzing how extended decay chains influence LHC search sensitivities.

Contribution

It provides reinterpretation of LHC search results for a natural NMSSM with a singlino LSP, highlighting how decay chain modifications affect exclusion limits.

Findings

Singlino LSP extends decay chains and softens final states.

LHC bounds are weaker but still significant in this model.

Model satisfies electroweak and flavor constraints.

Abstract

In this work, we present mass limits on gluinos and stops in a natural Next-to-Minimal Supersymmetric Standard Model (NMSSM) with a singlino as the lightest supersymmetric particle. Motivated by naturalness, we consider spectra with light higgsinos, sub-TeV third generation sparticles and gluinos well below the multi-TeV regime while the electroweak gauginos, the sleptons and the first and second generation squarks are decoupled. We check that our natural supersymmetry spectra satisfy all electroweak precision observables and flavour measurements as well as theoretical constraints. By reinterpreting the results from the 8 TeV ATLAS supersymmetry searches we present the 95% CL exclusion limits on the model. The results show that the presence of a singlino LSP can lengthen decay chains and soften the final state particle energies. Whilst this does reduce the strength of the bounds in some areas of parameter space, the LHC still displays good sensitivity to the model.