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arXiv · 2211.03799

Improved hot dark matter bound on the QCD axion

Alessio Notari·Fabrizio Rompineve·Giovanni Villadoro
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Abstract

We strengthen the cosmological bound on the axion mass, by solving the momentum-dependent Boltzmann equations for axion-pion scatterings and by using a phenomenological production rate derived from pion-pion scattering data, overcoming the breakdown of chiral perturbation theory. Using present cosmological datasets we obtain $m_a\leq 0.24~\text{eV}$. To further improve the bound and exploit the reach of upcoming cosmological surveys, reliable non-perturbative calculations above the QCD crossover are needed.

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Alessio Notari, Fabrizio Rompineve, Giovanni Villadoro. 2022-11-07. Improved hot dark matter bound on the QCD axion. https://arxiv.org/abs/2211.03799

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