Gravitino Dark Matter with Weak-Scale Right-Handed Sneutrino

Abstract

We consider cosmological implications of supersymmetric models with right-handed (s)neutrinos where the neutrino masses are purely Dirac-type. We pay particular attention to the case where gravitino is the lightest superparticle while one of the right-handed sneutrinos is next-to-the-lightest superparticle. We study constraints from big-bang nuleosynthesis and show that the constraints could be relaxed compared to the case without right-handed sneutrinos. As a result, the gravitino-dark-matter scenario becomes viable with relatively large value of the gravitino mass. We also discuss constraints from the structure formation; in our model, the free-streaming length of the gravitino dark matter may be as long as O(1 Mpc), which is comparable to the present observational upper bound on the scale of free-streaming.

18 pages, 6 figures

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• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• Big Bang Nucleosynthesis Constraints on Hadronically and Electromagnetically Decaying Relic Neutral Particles
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• Cosmological Constraints on Neutrino Injection
• Dark matter from late decays and the small-scale structure problems
• Grand Unification, Dark Matter, Baryon Asymmetry, and the Small Scale Structure of the Universe

Cited by in corpus (3)

• Hidden gauginos of an unbroken U(1): Cosmological constraints and phenomenological prospects
• Decaying Dark Matter in Supersymmetric Model and Cosmic-Ray Observations
• Cosmology of Gravitino LSP Scenario with Right-Handed Sneutrino NLSP