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arXiv · 2104.13390

Resurrecting Low-Mass Axion Dark Matter Via a Dynamical QCD Scale

Lucien Heurtier·Fei Huang·Tim M. P. Tait
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Abstract

In the framework where the strong coupling is dynamical, the QCD sector may confine at a much higher temperature than it would in the Standard Model, and the temperature-dependent mass of the QCD axion evolves in a non-trivial way. We find that, depending on the evolution of $\Lambda_{\mathrm{QCD}}$, the axion field may undergo multiple distinct phases of damping and oscillation leading generically to a suppression of its relic abundance. Such a suppression could therefore open up a wide range of parameter space, resurrecting in particular axion dark-matter models with a large Peccei-Quinn scale $f_a\gg 10^{12}~\mathrm{GeV}$, i.e., with a lighter mass than the standard QCD axion.

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Lucien Heurtier, Fei Huang, Tim M. P. Tait. 2021-04-27. Resurrecting Low-Mass Axion Dark Matter Via a Dynamical QCD Scale. https://doi.org/10.1007/jhep12(2021)216

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