Cosmological aspects of the clockwork axion

Abstract The clockwork axion refers to a family of aligned multi-axion models that lead to an exponential hierarchy between the scale of Peccei-Quinn symmetry breaking and the scale of the axion decay constant. The clockworking can bring the Peccei-Quinn-scale particles to within reach of collider e...

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Main Author: Andrew J. Long
Format: Article
Language:English
Published: SpringerOpen 2018-07-01
Series:Journal of High Energy Physics
Subjects:
Online Access:http://link.springer.com/article/10.1007/JHEP07(2018)066
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author Andrew J. Long
author_facet Andrew J. Long
author_sort Andrew J. Long
collection DOAJ
description Abstract The clockwork axion refers to a family of aligned multi-axion models that lead to an exponential hierarchy between the scale of Peccei-Quinn symmetry breaking and the scale of the axion decay constant. The clockworking can bring the Peccei-Quinn-scale particles to within reach of collider experiments. In this work we are interested in whether cosmological observations impose any new constraints on the clockwork axion. If the universe reheats above the scale of Peccei-Quinn breaking, then the ensuing cosmological phase transition produces a network of topological defects, which have a qualitatively different behavior from the string-wall network in the usual axion models. We estimate the relic abundances of axion dark matter and dark radiation that arise from the emission of axions by the defect network, and we infer a constraint on the scale of Peccei-Quinn breaking and the mass spectrum. We find that the defect contribution to the axion dark matter relic abundance is generally negligible. However, the defect production of relativistic axion dark radiation becomes significant if the scale of Peccei-Quinn symmetry breaking is larger than 100 TeV, and measurements of ΔN eff provide a new probe of this class of models.
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spelling doaj.art-6d7148d538d843c0953888029eb959c02022-12-22T01:52:51ZengSpringerOpenJournal of High Energy Physics1029-84792018-07-012018712910.1007/JHEP07(2018)066Cosmological aspects of the clockwork axionAndrew J. Long0Kavli Institute for Cosmological Physics, University of ChicagoAbstract The clockwork axion refers to a family of aligned multi-axion models that lead to an exponential hierarchy between the scale of Peccei-Quinn symmetry breaking and the scale of the axion decay constant. The clockworking can bring the Peccei-Quinn-scale particles to within reach of collider experiments. In this work we are interested in whether cosmological observations impose any new constraints on the clockwork axion. If the universe reheats above the scale of Peccei-Quinn breaking, then the ensuing cosmological phase transition produces a network of topological defects, which have a qualitatively different behavior from the string-wall network in the usual axion models. We estimate the relic abundances of axion dark matter and dark radiation that arise from the emission of axions by the defect network, and we infer a constraint on the scale of Peccei-Quinn breaking and the mass spectrum. We find that the defect contribution to the axion dark matter relic abundance is generally negligible. However, the defect production of relativistic axion dark radiation becomes significant if the scale of Peccei-Quinn symmetry breaking is larger than 100 TeV, and measurements of ΔN eff provide a new probe of this class of models.http://link.springer.com/article/10.1007/JHEP07(2018)066Cosmology of Theories beyond the SMBeyond Standard ModelTopological Strings
spellingShingle Andrew J. Long
Cosmological aspects of the clockwork axion
Journal of High Energy Physics
Cosmology of Theories beyond the SM
Beyond Standard Model
Topological Strings
title Cosmological aspects of the clockwork axion
title_full Cosmological aspects of the clockwork axion
title_fullStr Cosmological aspects of the clockwork axion
title_full_unstemmed Cosmological aspects of the clockwork axion
title_short Cosmological aspects of the clockwork axion
title_sort cosmological aspects of the clockwork axion
topic Cosmology of Theories beyond the SM
Beyond Standard Model
Topological Strings
url http://link.springer.com/article/10.1007/JHEP07(2018)066
work_keys_str_mv AT andrewjlong cosmologicalaspectsoftheclockworkaxion