Discovery potential for split supersymmetry with thermal dark matter

TL;DR

This paper explores the discovery potential of split supersymmetry models with thermal dark matter, focusing on Higgsino and wino dark matter candidates, and assesses their detectability via electron EDM and direct detection experiments.

Contribution

It identifies parameter space regions consistent with Higgs mass and dark matter abundance, analyzing experimental prospects for Higgsino and wino dark matter detection.

Findings

Higgsino dark matter models are within reach of planned experiments for scalar masses up to 10 PeV.

Wino dark matter models can be tested by future electron EDM experiments.

Complex phases do not prevent the detection prospects of the models.

Abstract

Supersymmetric extensions of the Standard Model with scalar superpartners above 10 TeV are well motivated since the Higgs boson mass can be explained by quantum corrections while maintaining gauge coupling unification. If supersymmetry breaking is transmitted to gauginos via anomaly mediation, the gaugino masses are loop suppressed compared to scalar masses, and the lightest supersymmetric particle is the Higgsino or wino, which can be the dark matter. In this setup, we identify the regions of parameter space that reproduce the observed Higgs boson mass and the thermal abundance of dark matter. We analyze the effects of complex phases in the gaugino mass parameters on the electron electric dipole moment (EDM) and the dark matter scattering cross section. We find that, for scalar masses up to 10 PeV and any size of the complex phases, the model with Higgsino dark matter is within reach of planned experiments -- Advanced ACME via electron EDM and LUX-ZEPLIN via dark matter direct detection -- with complementary discovery potentials, and the model with wino dark matter is within reach of future electron EDM experiments.