Natural gauge mediation with a bino NLSP at the LHC

TL;DR

This paper analyzes natural gauge mediation supersymmetry models with a bino-like neutralino NLSP at the LHC, deriving new experimental constraints on sparticle masses from diphoton search data, and discusses implications for model fine-tuning.

Contribution

It provides the first nontrivial experimental constraints on natural gauge mediation models with a neutralino NLSP decaying to photons, based on LHC diphoton search data.

Findings

Lightest stop > 580 GeV

Gluino > 1100 GeV

Charginos > 300-470 GeV

Abstract

Natural models of supersymmetry with a gravitino LSP provide distinctive signatures at the LHC. For a neutralino NLSP, sparticles can decay to two high energy photons plus missing energy. We use the ATLAS diphoton search with 4.8 fb^{-1} of data to place limits in both the stop-gluino and neutralino-chargino mass planes for this scenario. If the neutralino is heavier than 50 GeV, the lightest stop must be heavier than 580 GeV, the gluino heavier than 1100 GeV and charginos must be heavier than approximately 300-470 GeV. This provides the first nontrivial constraints in natural gauge mediation models with a neutralino NLSP decaying to photons, and implies a fine tuning of at least a few percent in such models.