Z-peaked excess in goldstini scenarios

TL;DR

This paper proposes that a specific goldstini supersymmetry scenario with a particular mass spectrum can explain a 3-sigma excess observed by ATLAS in events with Z bosons, jets, and missing energy, while remaining consistent with other experimental constraints.

Contribution

It introduces a novel goldstini SUSY model with a specific decay chain that accounts for the observed excess without conflicting with existing collider constraints.

Findings

A mass spectrum with gluino around 1000 GeV explains the excess.

The decay chain $ ilde g o g ilde o Z ilde G'$ reproduces the observed event rates.

The scenario is consistent with constraints from jets plus missing energy and CMS data.

Abstract

We study a possible explanation of a 3.0 $\sigma$ excess recently reported by the ATLAS Collaboration in events with Z-peaked same-flavour opposite-sign lepton pair, jets and large missing transverse momentum in the context of gauge-mediated SUSY breaking with more than one hidden sector, the so-called goldstini scenario. In a certain parameter space, the gluino two-body decay chain $\tilde g\to g\tilde\chi^0_{1,2}\to gZ\tilde G'$ becomes dominant, where $\tilde\chi^0_{1,2}$ and $\tilde G'$ are the Higgsino-like neutralino and the massive pseudo-goldstino, respectively, and gluino pair production can contribute to the signal. We find that a mass spectrum such as $m_{\tilde g}\sim 1000$ GeV, $m_{\tilde\chi^0_{1,2}}\sim 800$ GeV and $m_{\tilde G'}\sim 600$ GeV demonstrates the rate and the distributions of the excess, without conflicting with the stringent constraints from jets plus missing energy analyses and with the CMS constraint on the identical final state.