Nucleosynthesis constraints on a massive gravitino in neutralino dark matter scenarios

Journal Article · Thu Oct 01 00:00:00 EDT 2009 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2009/10/021· OSTI ID:22273072

Cyburt, Richard H. ^[1]; Ellis, John ^[2]; Fields, Brian D. ^[3]; Luo, Feng; Olive, Keith A. ^[4]

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1. Joint Institute for Nuclear Astrophysics (JINA), National Superconducting Cyclotron Laboratory (NSCL), Michigan State University, East Lansing, MI 48824 (United States)
2. TH Division, Physics Department, CERN, CH-1211 Geneva 23 (Switzerland)
3. Center for Theoretical Astrophysics, Departments of Astronomy and of Physics, University of Illinois, Urbana, IL 61801 (United States)
4. School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

The decays of massive gravitinos into neutralino dark matter particles and Standard Model secondaries during or after Big-Bang nucleosynthesis (BBN) may alter the primordial light-element abundances. We present here details of a new suite of codes for evaluating such effects, including a new treatment based on PYTHIA of the evolution of showers induced by hadronic decays of massive, unstable particles such as a gravitino. We present several sets of results obtained using these codes, including general constraints on the possible lifetime and abundance of an unstable particle decaying into neutralino dark matter under various hypotheses for its decay mechanism. We also develop an analytical treatment of non-thermal hadron propagation in the early universe, and use this to derive analytical estimates for light-element production and in turn on decaying particle lifetimes and abundances, which confirm our numerical results and illuminate the underlying physics. We then consider specifically the case of an unstable massive gravitino within the constrained minimal supersymmetric extension of the Standard Model (CMSSM). We present upper limits on its possible primordial abundance before decay for different possible gravitino masses, with CMSSM parameters along strips where the lightest neutralino provides all the astrophysical cold dark matter density. We do not find any CMSSM solution to the cosmological {sup 7}Li problem for small m{sub 3/2}. Discounting this, for m{sub 1/2} ∼ 500 GeV and tan β = 10 the other light-element abundances impose an upper limit m{sub 3/2}n{sub 3/2}/n{sub γ} ∼< 3 × 10{sup −12} GeV to ∼< 2 × 10{sup −13} GeV for m{sub 3/2} = 250 GeV to 1 TeV, which is similar in both the coannihilation and focus-point strips and somewhat weaker for tan β = 50, particularly for larger m{sub 1/2}. The constraints also weaken in general for larger m{sub 3/2}, and for m{sub 3/2} > 3 TeV we find a narrow range of m{sub 3/2}n{sub 3/2}/n{sub γ}, at values which increase with m{sub 3/2}, where the {sup 7}Li abundance is marginally compatible with the other light-element abundances.

• OSTI ID: 22273072
• Journal Information: Journal of Cosmology and Astroparticle Physics, Vol. 2009, Issue 10; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ASTROPHYSICS
COSMOLOGY
ELEMENT ABUNDANCE
GEV RANGE
GRAVITONS
HADRONIC PARTICLE DECAY
LITHIUM 7
MATHEMATICAL SOLUTIONS
NONLUMINOUS MATTER
NUCLEOSYNTHESIS
REST MASS
STANDARD MODEL
SUPERSYMMETRY
TEV RANGE
UNIVERSE
VISIBLE RADIATION