Direct and indirect detection of higgsino-like WIMPs: concluding the story of electroweak naturalness

TL;DR

This paper evaluates the detectability of higgsino-like WIMPs in natural supersymmetric models, showing that upcoming ton-scale detectors can fully probe these particles, potentially confirming or refuting electroweak naturalness.

Contribution

It provides the first comprehensive calculation of rescaled direct and indirect detection rates for higgsino-like WIMPs in natural SUSY models, highlighting the potential of future experiments to test these theories.

Findings

Ton-scale noble liquid detectors can probe the entire higgsino-like WIMP parameter space.

Detection prospects are limited for spin-dependent and indirect detection due to rescaling effects.

Experiments can either discover WIMPs or exclude electroweak naturalness in R-parity conserving SUSY models.

Abstract

Supersymmetric models which fulfill the conditions of electroweak naturalness generally contain light higgsinos with mass not too far from m_h ~125 GeV, while other sparticles can be much heavier. In R-parity conserving models, the lightest neutralino is then a higgsino-like WIMP (albeit with non-negligible gaugino components), with thermal relic density well below measured values. This leaves room for axions to function as co-dark matter particles. The local WIMP abundance is then expected to be below standard estimates, and direct and indirect detection rates must be accordingly rescaled. We calculate rescaled direct and indirect higgsino-like WIMP detection rates in SUSY models that fulfil the electroweak naturalness condition. In spite of the rescaling, we find that ton-scale noble liquid detectors can probe the entire higgsino-like WIMP parameter space, so that these experiments should either discover WIMPs or exclude the concept of electroweak naturalness in R-parity conserving natural SUSY models. Prospects for spin-dependent or indirect detection are more limited due in part to the rescaling effect.