Anapole moment of the lightest neutralino in the cMSSM

TL;DR

This paper investigates the electromagnetic anapole moment of the lightest neutralino within the cMSSM, highlighting its potential as a tool for dark matter detection and model constraints.

Contribution

It provides the first detailed calculation of the neutralino's anapole moment in the cMSSM, linking theoretical predictions with experimental constraints.

Findings

Anapole moment is non-zero but very small (< 10^{-3} GeV^{-2}).

Allowed parameter space is within reach of future dark matter direct detection experiments.

Anapole moment can serve as a complementary constraint in supersymmetric dark matter models.

Abstract

We study the anapole moment of the lightest neutralino in the constrained Minimal Supersymmetric Standard Model (cMSSM). The electromagnetic anapole is the only allowed electromagnetic form factor for Majorana fermions, such as the neutralino. Since the neutralino is the LSP in many versions of the MSSM and therefore a candidate for dark matter, its characterization through its electromagnetic properties is important both for particle physics and for cosmology. We perform a scan in the parameter space of the cMSSM and find that the anapole moment is different from zero albeit very small ($< 10^{-3}$ GeV$^{-2}$). Combined with experimental constraints like the Higgs mass and the DM relic density, the allowed region of parameter space lies within the reach of future direct DM searches. Thus, the anapole moment could be used as a complementary constraint when studying the parameter space of the cMSSM and other similar models.