Naturalness of Light Neutralino Dark Matter in pMSSM after LHC, XENON100 and Planck Data

Understand

We examine the possibility of a light (below 46 GeV) neutralino dark matter (DM) candidate within the 19-parameter phenomenological Minimal Supersymmetric Standard Model (pMSSM) in the light of various recent experimental results, especially from the LHC, XENON100, and Planck.

• We also study the extent of electroweak fine-tuning for such a light neutralino scenario in view of the null results from the searches for supersymmetry so far.
• Using a Markov Chain Monte Carlo likelihood analysis of the full pMSSM parameter space, we find that a neutralino DM with mass > 10 GeV can in principle still satisfy all the existing constraints.
• Our light neutralino solutions can be broadly divided into two regions: (i) The solutions in the 10 - 30 GeV neutralino mass range are highly fine-tuned and require the existence of light selectrons (below 100 GeV) in order to satisfy the observed DM relic density.