Search for PQ Axions

TL;DR

This paper reviews the recent developments and experimental efforts in searching for axions, a promising dark matter candidate originally proposed to solve the strong CP problem in quantum chromodynamics.

Contribution

It provides an overview of the evolving experimental landscape and new detection concepts for axion searches, highlighting recent progress and motivations.

Findings

Growing interest due to lack of signals in other dark matter searches

Development of novel detection methods for axions

Recent experimental proposals and advancements

Abstract

A major fraction of the mass content of the universe is composed of dark matter (DM), i.e. particles not interacting significantly with electromagnetic radiation, with ordinary matter or self-interacting (cold dark matter). The axion is originally proposed to solve the strong CP problem of quantum chromodynamics, but now emerges as an excellent cold DM candidate. The physics case of these particles has been considerably developed in recent years, and there are now useful guidelines and powerful motivations to attempt experimental detection. Admittedly, the lack of a positive signal of new physics at the high energy frontier, and in underground detectors searching for weakly interacting massive particles, is also contributing to the increase of interest in axion searches. The experimental landscape is rapidly evolving, with many novel detection concepts and new experimental proposals. The lastest development of the axion search efforts will be discussed.