title: Linking QCD axion models to their low-energy phenomenology
creator: Thormählen, Lennert Jarl
subject: ddc-530
subject: 530 Physics
description: The QCD axion is a well-motivated hypothetical particle beyond the Standard Model of particle physics. It can solve the strong CP problem and account for dark matter in the universe. An axion is a pseudo-Goldstone boson of a spontaneously broken global U(1) symmetry with a chiral anomaly in the strong sector. Such a minimal construction allows for a large number of alternative realisations with similar phenomenology. In this thesis, links between the underlying high-energy physics of axion models and the resulting observable phenomena at low energy are investigated. First, the property of periodicity along with its realisation and consequences at lower energies are studied. Subsequently, the usual leading logarithm approximation for the calculation of loop-induced flavour-changing effects is critically examined. A new model is developed that leads to large logarithmic enhancements and is valid up to the scale of spontaneous symmetry breaking. The phenomenology of this model in future searches for solar axions and at colliders is discussed. Finally, the spectrum of solar axions is evaluated, improving on the previous calculation and systematically quantifying the associated uncertainties for the first time. This could enable the distinction of axion models as well as the measurement of unknown solar quantities with the upcoming helioscope IAXO. It is also shown that this experiment is sensitive to a singular line in the spectrum originating from axion-nucleon interactions.
date: 2022
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/32346/1/thesis.pdf
identifier: DOI:10.11588/heidok.00032346
identifier: urn:nbn:de:bsz:16-heidok-323461
identifier:   Thormählen, Lennert Jarl  (2022) Linking QCD axion models to their low-energy phenomenology.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/32346/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng