Review of axino dark matter

TL;DR

This review discusses axino dark matter, a candidate arising from supersymmetric and Peccei-Quinn symmetry frameworks, highlighting its theoretical background and potential roles in cosmology.

Contribution

It provides a comprehensive overview of axino dark matter, including its theoretical motivation, properties, and the different scenarios for its role as dark matter.

Findings

Axino is a viable dark matter candidate.

Theoretical models link axino to solving hierarchy problems.

Multiple scenarios for axino dark matter are explored.

Abstract

We review the status of axino dark matter. Two hierarchy problems, the strong CP problem and the gauge hierarchy problem, have led to introducing into particle physics a spontaneously broken global Peccei-Quinn symmetry and a softly broken supersymmetry, respectively. Combining them implies the presence of not only an axion, but also of its scalar component, saxion, and their fermionic partner, axino. Among these, the axion and the axino are attractive dark matter candidates. Various possibilities for the axino as dark matter are discussed.