Imperfect axions with no domain wall problem
Abstract
Post-inflationary axion theories with domain wall number N>1 suffer from a domain wall problem. We show analytically, and confirm via simulations, that there is a region of phenomenologically viable parameter space for such theories with additional PQ-violating operators. Contrary to the conventional picture, in such theories the beyond-QCD PQ violation destroys the axion strings before the QCD axion potential becomes cosmologically relevant. This regime is realized for axion decay constants fa ≲ 1010 GeV, pointing to a QCD axion mass in the 10−3−10−2 eV range. The required additional PQ violation induces a neutron electric dipole moment within two orders of magnitude of the current experimental limit, placing it within the reach of upcoming neutron electric dipole moment experiments.
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BibTeX
@misc{gorghetto2026imperfect,
title = {{Imperfect axions with no domain wall problem}},
author = {Marco Gorghetto and Edward Hardy and Gilad Perez and Stefan Stelzl},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2608.27553},
eprint = {2608.27553},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.27553},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Imperfect axions with no domain wall problem
AU - Marco Gorghetto
AU - Edward Hardy
AU - Gilad Perez
AU - Stefan Stelzl
PY - 2026
DA - 2026/08/27
PB - arXiv
DO - 10.48550/arxiv.2608.27553
UR - https://arxiv.org/abs/2608.27553
AB - Post-inflationary axion theories with domain wall number N>1 suffer from a domain wall problem. We show analytically, and confirm via simulations, that there is a region of phenomenologically viable parameter space for such theories with additional PQ-violating operators. Contrary to the conventional picture, in such theories the beyond-QCD PQ violation destroys the axion strings before the QCD axion potential becomes cosmologically relevant. This regime is realized for axion decay constants f_a ≲ 10^10 GeV, pointing to a QCD axion mass in the 10^−3−10^−2 eV range. The required additional PQ violation induces a neutron electric dipole moment within two orders of magnitude of the current experimental limit, placing it within the reach of upcoming neutron electric dipole moment experiments.
ER -