The structure of multiple axion solutions and their emergence from flavour deconstruction
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Multi-axions solutions to the strong CP problem predict new axion states beyond the QCD axion band. They present a well-motivated departure from the canonical picture of the QCD axion band predicted by single-axion solutions, since they may modify the mass-photon-coupling relation. In this talk, I will explore the general structure of this type of solutions and identify the conditions under which axions can populate the different regions of the photon coupling-mass parameter space: the region to the right of the QCD axion band, the experimentally interesting region to its left, as well as scenarios in which the QCD axion band is itself displaced. Additionally, I will highlight the set of UV theories where these scenarios arise naturally. As a concrete UV completion, I will present a model in which the multiple axions solution is linked to the flavour puzzle, within the flavour deconstruction of QCD; showing the interesting parameter space and highlighting the different experimental probes that could provide information. All in all, I will highlight the systematic link between experimental axion searches, multi-axion phenomenology and the ultraviolet structure of solutions to the strong CP.