The axion mass in the post-inflationary scenario in a minimal scaling model — E8 Intelligence Research

We calculate the dark matter axion mass in the post-inflationary scenario in a minimal model with a set of classical field theory simulations on 12\,288³ grids. In the model, the Peccei-Quinn U(1) symmetry is broken by a complex scalar field at a temperature fₐ ~ 10¹¹ GeV, creating a string network. The strings become the boundaries of domain walls at the QCD transition, which draw the strings together and annihilate them. The decay of the strings and domain walls leaves behind axion radiation, with a comoving number density estimated to be 9.48(23)fₐ² H_*, normalised to unit scale factor when the axion mass is equal to the Hubble rate H_*. Using the most commonly quoted lattice results for the topological susceptibility, the dark matter axion mass in this minimal model is 17.46(84)\,μeV. This corresponds to a symmetry-breaking scale of 3.27(15) × 10¹¹\, GeV, and a haloscope resonant frequency of 4.22(20)\,GHz. We argue t Author: Andrew Stewart Caldin, Independent Researcher, UK. Part of the E8 Intelligence Research series. Platform: e8intelligence.com