Fine-tuning implications for complementary dark matter and LHC SUSY searches

TL;DR

This paper explores how different SUSY parameter regions with low fine-tuning can be tested through collider and dark matter experiments, emphasizing the complementary roles of LHC and direct detection in probing the CMSSM parameter space.

Contribution

It identifies two classes of low-fine-tuned SUSY scenarios and analyzes their detectability via LHC and dark matter experiments, highlighting the importance of combined search strategies.

Findings

Light gluinos/squarks detectable at LHC first run.

Heavier gluinos/squarks with Higgsino LSP detectable in dark matter experiments.

Combined collider and dark matter searches can test nearly all low-fine-tuned CMSSM regions.

Abstract

The requirement that SUSY should solve the hierarchy problem without undue fine-tuning imposes severe constraints on the new supersymmetric states. With the MSSM spectrum and soft SUSY breaking originating from universal scalar and gaugino masses at the Grand Unification scale, we show that the low-fine-tuned regions fall into two classes that will require complementary collider and dark matter searches to explore in the near future. The first class has relatively light gluinos or squarks which should be found by the LHC in its first run. We identify the multijet plus E_T^miss signal as the optimal channel and determine the discovery potential in the first run. The second class has heavier gluinos and squarks but the LSP has a significant Higgsino component and should be seen by the next generation of direct dark matter detection experiments. The combined information from the 7 TeV LHC run and the next generation of direct detection experiments can test almost all of the CMSSM parameter space consistent with dark matter and EW constraints, corresponding to a fine-tuning not worse than 1:100. To cover the complete low-fine-tuned region by SUSY searches at the LHC will require running at the full 14 TeV CM energy; in addition it may be tested indirectly by Higgs searches covering the mass range below 120 GeV.