Multiple Axions in Laboratory Experiments

TL;DR

This paper explores the theoretical implications of multiple axion-like particles on laboratory experiments, revealing how their interactions can significantly alter detection signals and offering new strategies for experimental identification.

Contribution

It develops general formulas for axion-photon oscillations involving multiple axions and analyzes their impact on various experimental search methods.

Findings

Multiple axions can enhance or suppress experimental signals.

Interference effects significantly alter observational signatures.

Experimental variations can help identify multiple axions' properties.

Abstract

Axions and axion-like particles generically appear in extensions of the Standard Model. While many searches assume only a single axion species, there may exist a whole spectrum of multiple such fields. We develop general formulas for axion-photon oscillations in the presence of multiple axions and analyze the implications for experimental searches, including light-shining-through-a-wall experiments, helioscopes and haloscopes. We demonstrate that axion multiplicity can qualitatively alter observational signatures, particularly through coherence and interference effects. Multiple axions can not only enhance signals compared to single axion scenarios, but also suppress them. We show that variations of experimental parameters and searches allow identifying contributions of multiple axions and obtaining information about their properties.