Nuclear Reaction Uncertainties, Massive Gravitino Decays and the Cosmological Lithium Problem - Astrophysics > Cosmology and Nongalactic AstrophysicsReportar como inadecuado




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Abstract: We consider the effects of uncertainties in nuclear reaction rates on thecosmological constraints on the decays of unstable particles during or afterBig-Bang nucleosynthesis BBN. We identify the nuclear reactions due tonon-thermal hadrons that are the most important in perturbing standard BBN,then quantify the uncertainties in these reactions and in the resultinglight-element abundances. These results also indicate the key nuclear processesfor which improved cross section data would allow different light-elementabundances to be determined more accurately, thereby making possible moreprecise probes of BBN and evaluations of the cosmological constraints onunstable particles. Applying this analysis to models with unstable gravitinosdecaying into neutralinos, we calculate the likelihood function for thelight-element abundances measured currently, taking into account the currentexperimental errors in the determinations of the relevant nuclear reactionrates. We find a region of the gravitino mass and abundance in which theabundances of deuterium, He4 and Li7 may be fit with chi^2 = 5.5, compared withchi^2 = 31.7 if the effects of gravitino decays are unimportant. The best-fitsolution is improved to chi^2 ~ 2.0 when the lithium abundance is taken fromglobular cluster data. Some such re-evaluation of the observed light-elementabundances and-or nuclear reaction rates would be needed if this region ofgravitino parameters is to provide a complete solution to the cosmological Li7problem.



Autor: Richard H. Cyburt, John Ellis, Brian D. Fields, Feng Luo, Keith A. Olive, Vassilis C. Spanos

Fuente: https://arxiv.org/



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