Uncovering Natural Supersymmetry via the interplay between the LHC and Direct Dark Matter Detection

TL;DR

This paper investigates the potential of the LHC and direct dark matter detection experiments to probe Natural Supersymmetry scenarios with higgsino-like dark matter, highlighting the complementarity of collider and direct detection methods.

Contribution

It demonstrates how optimized LHC searches at 13 TeV can extend dark matter mass limits beyond LEP2, and emphasizes the complementary roles of collider and direct detection experiments in exploring NSUSY.

Findings

LHC at 8 TeV cannot improve upon LEP2 limits for DM mass.

Optimized 13 TeV LHC searches can exclude DM masses up to 200-250 GeV.

LHC and direct detection experiments are highly complementary in probing NSUSY.

Abstract

We have explored Natural Supersymmetry (NSUSY) scenarios with low values of the $\mu$ parameter which are characterised by higgsino-like Dark Matter (DM) and compressed spectra for the lightest MSSM particles, $\chi^0_1$, $\chi^0_2$ and $\chi^\pm_1$. This scenario could be probed via monojet signatures, but as the signal-to-background ratio (S/B) is low we demonstrate that the 8 TeV LHC cannot obtain limits on the DM mass beyond those of LEP2. On the other hand, we have found, for the 13 TeV run of the LHC, that by optimising kinematical cuts we can bring the S/B ratio up to the 5(3)% level which would allow the exclusion of the DM mass up to 200(250) GeV respectively, significantly extending LEP2 limits. Moreover, we have found that LUX/XENON1T and LHC do play very complementary roles in exploring the parameter space of NSUSY, as the LHC has the capability to access regions where DM is quasi-degenerate with other higgsinos, which are challenging for direct detection experiments.