Direct detection rate of heavy Higgsino-like and Wino-like dark matter

TL;DR

This paper analyzes the suppressed direct detection signals of heavy Higgsino-like and Wino-like dark matter candidates, incorporating subleading effects and nuclear corrections to refine predictions for experimental searches.

Contribution

It computes the first-order power corrections in the heavy WIMP expansion and evaluates nuclear modifications, providing a more accurate assessment of detection prospects.

Findings

Pure Higgsino dark matter signals are below neutrino backgrounds at TeV masses.

Nuclear corrections significantly affect the predicted cross sections.

Subleading effects and nuclear modifications are crucial for interpreting experimental bounds.

Abstract

A large class of viable dark matter models contain a WIMP candidate that is a component of a new electroweak multiplet whose mass $M$ is large compared to the electroweak scale $m_W$. A generic amplitude-level cancellation in such models yields a severe suppression of the cross section for WIMP-nucleon scattering, making it important to assess the impact of formally subleading effects. The power correction of order $m_W/M$ to the heavy WIMP limit is computed for electroweak doublet (Higgsino-like) dark matter candidates, and a modern model of nuclear modifications to the free nucleon cross section is evaluated. Corrections to the pure Higgsino limit are determined by a single parameter through first order in the heavy WIMP expansion. Current and projected experimental bounds on this parameter are investigated. The direct detection signal in the pure Higgsino limit remains below neutrino backgrounds for WIMPs in the TeV mass range. Nuclear corrections are applied also to the heavy Wino case, completing the investigation of combined subleading effects from perturbative QCD, $1/M$ power corrections, and nuclear modifications.