Toward the Effective Light and Heavy QCD Axion Scenarios

TL;DR

This paper explores the parameter space of light and heavy QCD axion models, analyzing axion mass and decay constant ratios in single and multiple axion scenarios to understand their similarities and differences.

Contribution

It provides a comparative analysis of axion mass and decay constant ratios in light and heavy QCD axion models, extending findings from two-axion to multi-axion cases.

Findings

Axion mass ratios are similar in light and heavy scenarios.

Axion decay constant ratios are oppositely aligned in these scenarios.

Results are generalized to multiple axion models.

Abstract

In this work, we investigate the effective parameter space associated with the axion mass and the axion decay constant in both the light and heavy QCD axion scenarios. We initiate our discussion by considering the simplest case of two axions, quantitatively analyzing the parameter space in these two distinct scenarios. We find that the axion mass ratios exhibit a high degree of similarity in these two situations. In contrast, the ratios of axion decay constants display a complete opposition. Furthermore, we generalize our conclusions to encompass the case of multiple axions.