Cosmologically safe QCD axion as a present from extra dimension

Abstract

We propose a QCD axion model where the origin of PQ symmetry and suppression of axion isocurvature perturbations are explained by introducing an extra dimension. Each extra quark-antiquark pair lives on branes separately to suppress PQ breaking operators. The size of the extra dimension changes after inflation due to an interaction between inflaton and a bulk scalar field, which implies that the PQ symmetry can be drastically broken during inflation to suppress undesirable axion isocurvature fluctuations.

6 pages

References in corpus (3)

• An Improved Experimental Limit on the Electric Dipole Moment of the Neutron
• Symmetries and Strings in Field Theory and Gravity
• A theory of extra radiation in the Universe

Cited by in corpus (14)

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• Axion Isocurvature and Magnetic Monopoles
• Dynamics of Peccei-Quinn Breaking Field after Inflation and Axion Isocurvature Perturbations
• Strongly broken Peccei-Quinn symmetry in the early Universe
• Axion Misalignment Driven to the Bottom
• Adiabatic suppression of the axion abundance and isocurvature due to coupling to hidden monopoles
• Isocurvature Perturbations of Dark Energy and Dark Matter from the Swampland Conjecture
• Cosmologically safe QCD axion without fine-tuning
• A natural and simple UV completion of the QCD axion model
• Cosmological Perturbations of Axion with a Dynamical Decay Constant
• Baryon Asymmetric Universe from Spontaneous CP Violation