• Corpus ID: 238634373

Free Streaming Length of Axion-Like Particle After Oscillon/ I-ball Decays

@inproceedings{Imagawa2021FreeSL,
  title={Free Streaming Length of Axion-Like Particle After Oscillon/ I-ball Decays},
  author={Kaname Imagawa and Masahiro Kawasaki and Kai Murai and Hiromasa Nakatsuka and Eisuke Sonomoto},
  year={2021}
}

• Kaname Imagawa, M. Kawasaki, +2 authors Eisuke Sonomoto
• Published 12 October 2021
• Physics

Axion-like particles (ALPs) are pseudoscalar bosons predicted by string theory. The ALPs have a shallower potential than a quadratic one, which induces the instability and can form the solitonic object called oscillon/I-ball. Although the lifetime of oscillons can be very long for some type of potentials, they finally decay until the present. We perform the numerical lattice simulations to investigate the decay process of oscillons and evaluate the averaged momentum of ALPs emitted from the oscillon decay. It is found that, if oscillons decay in the early universe, the free-streaming length of ALPs becomes too long to explain the small-scale observations of the matter power spectrum. We show that oscillons with long lifetimes can change the density fluctuations on small scales, which leads to stringent constraints on the ALP mass and the oscillon lifetime.