Theoretical Uncertainties in the Calculation of Supersymmetric Dark Matter Observables

TL;DR

This paper assesses the theoretical uncertainties in supersymmetric dark matter predictions within the MSSM, revealing that current computational methods can produce discrepancies much larger than experimental errors, especially in GUT models and electroweak scenarios.

Contribution

It provides a comprehensive comparison of state-of-the-art computational pipelines, highlighting significant uncertainties in dark matter observable calculations in supersymmetric models.

Findings

Discrepancies in relic density calculations can be several orders of magnitude.

Uncertainties are especially large in GUT models and electroweak-sensitive scenarios.

Theoretical uncertainties impact the interpretation of experimental dark matter searches.

Abstract

We estimate the current theoretical uncertainty in supersymmetric dark matter predictions by comparing several state-of-the-art calculations within the minimal supersymmetric standard model (MSSM). We consider standard neutralino dark matter scenarios -- coannihilation, well-tempering, pseudoscalar resonance -- and benchmark models both in the pMSSM framework and in frameworks with Grand Unified Theory (GUT)-scale unification of supersymmetric mass parameters. The pipelines we consider are constructed from the publicly available software packages SOFTSUSY, SPheno, FeynHiggs, SusyHD, micrOMEGAs, and DarkSUSY. We find that the theoretical uncertainty in the relic density as calculated by different pipelines, in general, far exceeds the statistical errors reported by the Planck collaboration. In GUT models, in particular, the relative discrepancies in the results reported by different pipelines can be as much as a few orders of magnitude. We find that these discrepancies are especially pronounced for for cases where the dark matter physics relies critically on calculations related to electroweak symmetry breaking, which we investigate in detail, and for coannihilation models, where there is heightened sensitivity to the sparticle spectrum. The dark matter annihilation cross section today and the scattering cross section with nuclei also suffer appreciable theoretical uncertainties, which, as experiments reach the relevant sensitivities, could lead to uncertainty in conclusions regarding the viability or exclusion of particular models.