Isocurvature bounds on axions revisited
- Departamento de Fisica Teorica C-XI, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain)
- Laboratoire d'Annecy-le-vieux de Physique Theorique, BP110, F-74941 Annecy-le-Vieux Cedex (France)
The axion is one of the best motivated candidates for particle dark matter. We study and update the constraints imposed by the recent CMB and LSS experiments on the mass of axions produced by the misalignment mechanism, as a function of both the inflationary scale and the reheating temperature. Under some particular although not unconventional assumptions, the axion induces isocurvature perturbations with an amplitude too large to be compatible with observations. Specifically, for inflation taking place at intermediate energy scales, we derive some restrictive limits which can only be evaded by assuming an efficient reheating mechanism, with T{sub rh}>10{sup 11} GeV. Chaotic inflation with a quadratic potential is still compatible with the axion scenario, provided that the Peccei-Quinn scale f{sub a} is close to 10{sup 10} or 10{sup 11} GeV. Isocurvature bounds eliminate the possibility of a larger f{sub a} and a small misalignment angle. We find that isocurvature constraints on the axion scenario must be taken into account whenever the scale of inflation is above 10{sup 12} GeV; below this scale, axionic isocurvature modes are too small to be probed by current observations.
- OSTI ID:
- 20933290
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 75, Issue 10; Other Information: DOI: 10.1103/PhysRevD.75.103507; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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