Natural SUSY Endures

TL;DR

This paper evaluates the impact of early LHC searches on natural supersymmetry, finding that key particles like stops, sbottoms, and gluinos are constrained but natural SUSY scenarios still remain viable.

Contribution

It provides a comprehensive collider simulation analysis of LHC search limits on natural SUSY particles, highlighting surviving parameter space and future prospects.

Findings

Stops and sbottoms must be heavier than 200-300 GeV.

Gluino must be heavier than 600-800 GeV.

Natural SUSY remains viable after initial LHC data.

Abstract

The first 1/fb of LHC searches have set impressive limits on new colored particles decaying to missing energy. We address the implication of these searches for naturalness in supersymmetry (SUSY). General bottom-up considerations of natural electroweak symmetry breaking show that higgsinos, stops, and the gluino should not be too far above the weak scale. The rest of the spectrum, including the squarks of the first two generations, can be heavier and beyond the current LHC reach. We have used collider simulations to determine the limits that all of the 1/fb searches pose on higgsinos, stops, and the gluino. We find that stops and the left-handed sbottom are starting to be constrained and must be heavier than about 200-300 GeV when decaying to higgsinos. The gluino must be heavier than about 600-800 GeV when it decays to stops and sbottoms. While these findings point toward scenarios with a lighter third generation split from the other squarks, we do find that moderately-tuned regions remain, where the gluino is just above 1 TeV and all the squarks are degenerate and light. Among all the searches, jets plus missing energy and same-sign dileptons often provide the most powerful probes of natural SUSY. Overall, our results indicate that natural SUSY has survived the first 1/fb of data. The LHC is now on the brink of exploring the most interesting region of SUSY parameter space.