Baryon isocurvature fluctuations at small scales and baryonic dark matter
Abstract
A model of baryogenesis is described which gives rise to fluctuations in baryon number that are large on small scales but of low amplitude on large scales. This provides a mechanism for primordial black-hole formation, and allows the possibility of a critical density of dark matter in baryonic (and antibaryonic) form. Since high-density regions naturally possess both signs of baryonic excess, our model also predicts a small fraction of the mass density of the Universe to be in the form of compact antibaryonic regions. These objects may be observable via a redshifted annihilation feature in the diffuse extragalactic γ-ray background, as both steady sources of γ-ray radiation and annihilation-powered γ-ray bursters at cosmological distances, by a distortion of the spectrum of the 3K background radiation, or by the presence of antihelium nuclei as a rare component of high-energy cosmic rays.
- Publication:
-
Physical Review D
- Pub Date:
- May 1993
- DOI:
- 10.1103/PhysRevD.47.4244
- Bibcode:
- 1993PhRvD..47.4244D
- Keywords:
-
- 98.70.Vc;
- 95.35.+d;
- 98.80.Hw;
- Background radiations;
- Dark matter