Imperfect Axion Precludes the Domain Wall Problem

Fuente: arXiv
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Auteur principal: Zhang, Yue
Format: Preprint
Publié: 2023
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author Zhang, Yue
author_facet Zhang, Yue
contents The QCD axion needs not be an exact pseudoscalar for solving the strong CP problem. Its imperfectness can play a profound role cosmologically. We propose effective operators, where the Peccei-Quinn field linearly couples to Standard Model particles, provide a dynamical solution to the domain wall problem that prevails in post-inflationary axion models with discrete symmetry. Such interactions generate a thermal potential that drives the axion field to a universal value throughout the universe at high temperatures thus preventing the birth of domain walls when the QCD potential switches on. We discuss generic conditions for this mechanism to work and several concrete examples. Combining with existing electric dipole moment and fifth force constraints, a lower bound on the axion mass is obtained around $10^{-5}$\,eV. Our findings make a strong case for complementary axion searches with both quality preserving and violating interactions.
format Preprint
id arxiv_https___arxiv_org_abs_2305_15495
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Imperfect Axion Precludes the Domain Wall Problem
Zhang, Yue
High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
The QCD axion needs not be an exact pseudoscalar for solving the strong CP problem. Its imperfectness can play a profound role cosmologically. We propose effective operators, where the Peccei-Quinn field linearly couples to Standard Model particles, provide a dynamical solution to the domain wall problem that prevails in post-inflationary axion models with discrete symmetry. Such interactions generate a thermal potential that drives the axion field to a universal value throughout the universe at high temperatures thus preventing the birth of domain walls when the QCD potential switches on. We discuss generic conditions for this mechanism to work and several concrete examples. Combining with existing electric dipole moment and fifth force constraints, a lower bound on the axion mass is obtained around $10^{-5}$\,eV. Our findings make a strong case for complementary axion searches with both quality preserving and violating interactions.
title Imperfect Axion Precludes the Domain Wall Problem
topic High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2305.15495