More Energy, More Searches, but the pMSSM Lives On

TL;DR

This study evaluates the LHC's ability to probe the pMSSM parameter space, showing current exclusions and highlighting the persistence of viable models with light superpartners and low fine-tuning despite null search results.

Contribution

It provides an updated analysis of LHC SUSY searches' impact on the pMSSM, incorporating all relevant ATLAS data as of September 2012, and discusses implications for future experiments.

Findings

Approximately one-third of pMSSM models are excluded by current searches.

Light gluinos, squarks, and stops/sbottoms remain viable below 700 GeV.

Increased luminosity at 8 TeV is unlikely to significantly improve search reach.

Abstract

We further examine the capability of the 7 and 8 TeV LHC to explore the parameter space of the p(henomenological)MSSM with neutralino LSPs. Here we present an updated study employing all of the relevant ATLAS SUSY analyses, as well as all relevant LHC non-MET searches, whose data were publically available as of mid-September 2012. We find that roughly 1/3 of our pMSSM model points are excluded at present with an important role being played by both the heavy flavor and multi-lepton searches, as well as those for heavy stable charged particles. Nonetheless, we find that light gluinos, 1st/2nd generation squarks, and stop/sbottoms (\lsim 400-700 GeV), as well as models with 1% fine-tuning or better, are still viable in the pMSSM. In addition, we see that increased luminosity at 8 TeV is unlikely to significantly improve the reach of the "vanilla" searches. The impact of these null searches on the SUSY sparticle spectrum is discussed in detail and the implications of these results for models with low fine-tuning, a future lepton collider and dark matter searches are examined.