Topology in QCD and the axion abundance

@article{Kitano2015TopologyIQ,
  title={Topology in QCD and the axion abundance},
  author={Ryuichiro Kitano and Norikazu Yamada},
  journal={Journal of High Energy Physics},
  year={2015},
  volume={2015},
  pages={1-16}
}
A bstractThe temperature dependence of the topological susceptibility in QCD, χt, essentially determines the abundance of the QCD axion in the Universe, and is commonly estimated, based on the instanton picture, to be a certain negative power of temperature. While lattice QCD should be able to check this behavior in principle, the temperature range where lattice QCD works is rather limited in practice, because the topological charge is apt to freezes at high temperatures. In this work, two… 
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If the QCD axion is a significant component of dark matter, and if the universe was once hotter than a few hundred MeV, the axion relic abundance depends on the function $\chi(T)$, the
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The Standard Model (SM) in the elementary particle physics describes the fundamental physical law in nature and, in principle, provides us infinitely accurate predictions, which are consistent with
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