Nuclear Reaction Uncertainties, Massive Gravitino Decays and the Cosmological Lithium Problem

Abstract

We consider the effects of uncertainties in nuclear reaction rates on the cosmological constraints on the decays of unstable particles during or after Big-Bang nucleosynthesis (BBN). We identify the nuclear reactions due to non-thermal hadrons that are the most important in perturbing standard BBN, then quantify the uncertainties in these reactions and in the resulting light-element abundances. These results also indicate the key nuclear processes for which improved cross section data would allow different light-element abundances to be determined more accurately, thereby making possible more precise probes of BBN and evaluations of the cosmological constraints on unstable particles. Applying this analysis to models with unstable gravitinos decaying into neutralinos, we calculate the likelihood function for the light-element abundances measured currently, taking into account the current experimental errors in the determinations of the relevant nuclear reaction rates. We find a region of the gravitino mass and abundance in which the abundances of deuterium, He4 and Li7 may be fit with chi^2 = 5.5, compared with chi^2 = 31.7 if the effects of gravitino decays are unimportant. The best-fit solution is improved to chi^2 ~ 2.0 when the lithium abundance is taken from globular cluster data. Some such re-evaluation of the observed light-element abundances and/or nuclear reaction rates would be needed if this region of gravitino parameters is to provide a complete solution to the cosmological Li7 problem.

24 pages, 10 figures

References in corpus (4)

• Big Bang Nucleosynthesis Constraints on Hadronically and Electromagnetically Decaying Relic Neutral Particles
• A Bitter Pill: The Primordial Lithium Problem Worsens
• Evaluation of Modern 3He(alpha,gamma)7Be Data
• Lithium abundances of halo dwarfs based on excitation temperature. I. LTE

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• Cosmological solutions to the Lithium problem: Big-bang nucleosynthesis with photon cooling, $X$-particle decay and a primordial magnetic field
• Superstring-Inspired Particle Cosmology: Inflation, Neutrino Masses, Leptogenesis, Dark Matter & the SUSY Scale
• Slow and Safe Gravitinos
• Anomalous $Z^{\prime }$ bosons for anomalous $B$ decays
• Solution to Big-Bang Nucleosynthesis in Hybrid Axion Dark Matter Model
• Effects of an Intermediate Mass Sterile Neutrino Population on the Early Universe
• Gravitino Thermal Production, Dark Matter, and Reheating of the Universe
• Minimal Nambu-Goldstone Higgs Model in Supersymmetric SU(5) Revisited
• New Bounds on Heavy QCD Axions from Big Bang Nucleosynthesis