Axion cosmology with long-lived domain walls

Abstract

We investigate the cosmological constraints on axion models where the domain wall number is greater than one. In these models, multiple domain walls attached to strings are formed, and they survive for a long time. Their annihilation occurs due to the effects of explicit symmetry breaking term which might be raised by Planck-scale physics. We perform three-dimensional lattice simulations and compute the spectra of axions and gravitational waves produced by long-lived domain walls. Using the numerical results, we estimated relic density of axions and gravitational waves. We find that the existence of long-lived domain walls leads to the overproduction of cold dark matter axions, while the density of gravitational waves is too small to observe at the present time. Combining the results with other observational constraints, we find that the whole parameter region of models are excluded unless an unacceptable fine-tuning exists.

40 pages, 13 figures; revised version of the manuscript, accepted for publication in JCAP

References in corpus (6)

• An Improved Experimental Limit on the Electric Dipole Moment of the Neutron
• Theory and Numerics of Gravitational Waves from Preheating after Inflation
• Improved estimation of radiated axions from cosmological axionic strings
• Axions and the white dwarf luminosity function
• Discrete R Symmetries and Domain Walls
• Cosmological Constraints on Isocurvature and Tensor Perturbations

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