Status of Natural Supersymmetry from the GmSUGRA in Light of the current LHC Run-2 and LUX data

TL;DR

This study explores natural supersymmetry within GmSUGRA, demonstrating compatibility with current experimental constraints, identifying viable dark matter scenarios, and analyzing collider detection prospects with a focus on electroweak fine-tuning.

Contribution

It provides a detailed analysis of low fine-tuning supersymmetric models in GmSUGRA, identifying parameter space consistent with dark matter and collider constraints, and presents benchmark points for future searches.

Findings

Viable dark matter scenarios include Z-pole, Higgs-pole, and Higgsino LSP.

Current LHC data excludes certain Higgsino-dominant neutralino masses up to 460 GeV.

Electroweak fine-tuning around 20 remains compatible with experimental bounds.

Abstract

We study natural supersymmetry in the Generalized Minimal Supergravity (GmSUGRA). For the parameter space with low energy electroweak fine-tuning measures less than 50, we are left with only the $Z$-pole, Higgs-pole and Higgsino LSP scenarios for dark matter (DM). We perform the focused scans for such parameter space and find that it satisfies various phenomenological constraints and is compatible with the current direct detection bound on neutralino DM reported by the LUX experiment. Such parameter space also has solutions with correct DM relic density besides the solutions with DM relic density smaller or larger than 5$\sigma$ WMAP9 bounds. We present five benchmark points as examples. In these benchmark points, gluino and the first two generations of squarks are heavier than 2 TeV, stop $\tilde t_{1,2}$ are in the mass range $[1,2]$ TeV, while sleptons are lighter than 1 TeV. Some part of the parameter space can explain the muon anomalous magnetic moment within 3$\sigma$ as well. We also perform the collider study of such solutions by implementing and comparing with relevant studies done by the ATLAS and CMS Collaborations. We find that the points with Higgsino dominant $\tilde{\chi}_2^0/\tilde{\chi_1}^\pm$ mass up to $300$ GeV are excluded in $Z$-pole scenario while for Higgs-pole scenario, the points with $\tilde{\chi}_2^0$ mass up to $460$ GeV are excluded. We also notice that the Higgsino LSP points in our present scans are beyond the reach of present LHC searches. Next, we show that for both the $Z$-pole and Higgs-pole scenarios, the points with electroweak fine-tuning measure around 20 do still survive.