http://arxiv.org/abs/2211.13074
We propose an alternative scenario of axion misalignment mechanism based on nontrivial interplay between axion and a light dilaton in the early universe. Dark matter abundance is still sourced by the initial misalignment of axion field, whose motion along the potential kicks the dilaton field away from its minimum, and dilaton starts to oscillate later with a delayed onset time for oscillation and a relatively large misalignment value due to kick, eventually the dilaton dominates over axion in their energy densities and dilaton is identified as dark matter. The kick effect due to axion motion is the most significant if the initial field value of dilaton is near its minimum, therefore we call this scenario axion free-kick misalignment mechanism, where axion plays the role similar to a football player. Dark matter abundance can be obtained with a lower axion decay constant compared to the conventional misalignment mechanism.
L. Xu and S. Yun
Thu, 24 Nov 22
65/71
Comments: 4 pages, 3 figures, one appendix. comments welcome