ATLAS on-Z Excess via gluino-Higgsino-singlino decay chains in the NMSSM

TL;DR

This paper proposes that the NMSSM can explain the ATLAS on-Z excess through gluino decays involving Higgsino and singlino-like neutralinos, also accounting for dark matter relic density.

Contribution

It introduces a specific decay chain in the NMSSM that explains the ATLAS excess and links it to dark matter relic density, providing a comprehensive scenario.

Findings

The NMSSM can account for the ATLAS on-Z excess.

The singlino-like neutralino explains dark matter relic density.

Predictions for Higgs sector searches at the LHC are discussed.

Abstract

Recently the ATLAS experiment has reported 3.0 sigma excess in an on-Z signal region in searches for supersymmetric particles. We find that the next-to-minimal supersymmetric standard model can explain this excess by the production of gluinos which mainly decay via $\tilde{g} \to g \tilde{\chi}^0_{2,3} \to g Z \tilde{\chi}^0_{1}$ where $\tilde{\chi}^0_{2,3}$ and $\tilde{\chi}^0_1$ are the Higgsino and the singlino-like neutralinos, respectively. We show that the observed dark matter density is explained by the thermal relic density of the singlino-like neutralino, simultaneously. We also discuss the searches for the Higgs sector of this scenario at the Large Hadron Collider.