Primordial non-Gaussianity in models with dark matter isocurvature fluctuations

Journal Article · Tue Sep 15 04:00:00 EDT 2009 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.80.063524· OSTI ID:21322698

Takahashi, Tomo ^[1]; Yamaguchi, Masahide ^[2]; Yokoyama, Shuichiro ^[3]

---

1. Department of Physics, Saga University, Saga 840-8502 (Japan)
2. Department of Physics and Mathematics, Aoyama Gakuin University, Sagamihara 229-8558 (Japan)
3. Department of Physics and Astrophysics, Nagoya University, Aichi 464-8602 (Japan)

We investigate primordial non-Gaussianity and dark matter isocurvature fluctuations in the modulated reheating and the curvaton scenarios. In these scenarios, a large non-Gaussianity can be generated; on the other hand, depending on how dark matter is produced, too large isocurvature fluctuations can also arise, which is inconsistent with current observations. In this paper, we study this issue in a mixed scenario where the curvature fluctuations can also be produced from the inflaton fluctuations as well as those from a light scalar field such as the modulus and the curvaton. We show that primordial fluctuations can be highly non-Gaussian without conflicting with the current constraint on isocurvature fluctuations for such mixed scenarios. However, if the constraint on isocurvature fluctuations becomes severer as expected by the Planck satellite, f{sub NL}, a nonlinearity parameter for adiabatic fluctuations, should be very small as f{sub NL} < or approx. 3, which would give interesting implications for the generation mechanism of dark matter. Non-Gaussianity from isocurvature fluctuations is also discussed in these scenarios.

• OSTI ID: 21322698
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 6 Vol. 80; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
FLUCTUATIONS
NONLINEAR PROBLEMS
NONLUMINOUS MATTER
SCALAR FIELDS