Axinos as Dark Matter Particles

TL;DR

This paper explores axinos as viable dark matter candidates within supersymmetric models, discussing their production mechanisms, possible mass hierarchies, and implications for collider and astrophysical signals.

Contribution

It introduces the role of axinos as dark matter particles, analyzing their production, mass scenarios, and potential experimental signatures in supersymmetric frameworks.

Findings

Axinos can be the LSP or heavier, affecting dark matter composition.

Thermal scatterings and out-of-equilibrium decays produce axinos in correct abundance.

Different collider and astrophysical signals depend on supersymmetric spectrum and R-parity.

Abstract

The identification of dark matter in our particle physics model is still a very open question. Here we will argue that axinos can be successful dark matter candidates in models with supersymmetry and the axion solution of the strong CP problem. Axinos can be the lightest supersymmetric particle (LSP), or can be heavier than the LSP. Axinos can be produced in the right abundance by thermal scatterings and if they are the LSP also by out of equilibrium decays of the lightest superpartner of SM fields (LSPSMs). On the other hand heavier (not LSP) axinos can generate a part of the neutralino LSP dark matter. Depending on the nature of the supersymmetric spectrum, and if R-parity is strictly conserved or slightly broken, very different signals of the LSP axino scenario can arise at colliders and in astrophysics.