Cosmo-26

The post-inflationary axion mass in a minimal scaling model

Not scheduled

20m

Gorlaeus gebouw (Leiden University)

Talk Early Universe

Speaker

Prof. Mark Hindmarsh (University of Helsinki, University of Sussex)

Description

We calculate the dark matter axion mass in the post-inflationary scenario in a minimal model with a set of numerical simulations on $12288^3$ grids, the largest to date. The minimal model contains only one extra scalar field which breaks the Peccei-Quinn U(1) symmetry at a temperature $f_a \sim 10^{11}$ GeV, creating a string network, which is assumed not to have a Standard Model Higgs condensate in the string core. 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 axions, which can constitute part or all of the dark matter. We report on the measurements of the comoving axion number density following the collapse of the string-wall system, and give an accurate estimate of the dark matter axion mass in the scaling scenario.