PT Journal
AU Caputo, A
   Reig, M
TI Cosmic implications of a low-scale solution to the axion domain wall problem
SO Physical Review D
JI Phys. Rev. D
PY 2019
BP 063530
EP 10pp
VL 100
IS 6
DI 10.1103/PhysRevD.100.063530
LA English
AB The post-inflationary breaking of Peccei-Quinn (PQ) symmetry can lead to the cosmic domain wall catastrophe. In this paper we show how to avoid domain walls by implementing the instanton interference effect with a new interaction which itself breaks PQ symmetry and confines at an energy scale smaller than Lambda(QCD). We give a general description of the mechanism and consider its cosmological implications and constraints within a minimal model. Contrary to other mechanisms, we do not require an inverse phase transition or fine-tuned bias terms. Incidentally, the mechanism leads to the introduction of new self-interacting dark matter candidates and the possibility of producing gravitational waves in the frequency range of SKA. Unless a fine-tuned hidden sector is introduced, the mechanism predicts a QCD axion in the mass range 1-15 meV.
ER