Solution to Big-Bang Nucleosynthesis in Hybrid Axion Dark Matter Model

Physics Letters B (Impact Factor: 6.13). 02/2012; 718(3). DOI: 10.1016/j.physletb.2012.11.007
Source: arXiv


Following a recent suggestion of axion cooling of photons between the
nucleosynthesis and recombination epochs in the Early Universe, we investigate
a hybrid model with both axions and relic supersymmetric particles. In this
model we demonstrate that the 7Li abundance can be consistent with observations
without destroying the important concordance of deuterium abundance.

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Available from: Yamac Pehlivan, Apr 20, 2014
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    • "Unfortunately, this discrepancy is not immediately remedied simply by the presence of new light species, and the detailed model-building necessary to address this tension is beyond the scope of this paper. However, the 7 Li problem does present another exciting opportunity for the possible discovery of new physics [48] [49] [50] [51] [52]. "
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    ABSTRACT: We consider the effects of new light species on the Cosmic Microwave Background. In the massless limit, these effects can be parameterized in terms of a single number, the relativistic degrees of freedom. We perform a thorough survey of natural, minimal models containing new light species and numerically calculate the precise contribution of each of these models to this number in the framework of effective field theory. After reviewing the relevant details of early universe thermodynamics, we provide a map between the parameters of any particular theory and the predicted effective number of degrees of freedom. We then use this map to interpret the recent results from the Cosmic Microwave Background survey done by the Planck satellite. Using this data, we present new constraints on the parameter space of several models containing new light species. Future measurements of the Cosmic Microwave Background can be used with this map to further constrain the parameter space of all such models.
    Journal of High Energy Physics 03/2013; 2013(12). DOI:10.1007/JHEP12(2013)058 · 6.11 Impact Factor
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    ABSTRACT: Non-standard model solutions to the łi7 problem are discussed. Particular attention is given to the possibility of a relatively long lived gravitino decay affecting the light element abundances. Gravitinos with masses between 4-5 TeV could significantly reduce the final łi7 abundance. Alternatively, a possible variation in the fundamental constants may also affect the łi7 abundance. In both cases, reduced łi7 is accompanied by an increased D/H abundance. This may have implications for the chemical evolution in quasar absorption systems.
    01/2012; 22:197-.
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    ABSTRACT: Standard Big Bang Nucleosynthesis at the baryon density determined by the microwave anisotropy spectrum predicts an excess of \li7 compared to observations by a factor of 4-5. In contrast, BBN predictions for D/H are somewhat below (but within ~2 \sigma) of the weighted mean of observationally determined values from quasar absorption systems. Solutions to the \li7 problem which alter the nuclear processes during or subsequent to BBN, often lead to a significant increase in the deuterium abundance consistent with the highest values of D/H seen in absorption systems. Furthermore, the observed D/H abundances show considerable dispersion. Here, we argue that those systems with D/H \simeq 4 \times 10^{-5} may be more representative of the primordial abundance and as a consequence, those systems with lower D/H would necessarily have been subject to local processes of deuterium destruction. This can be accounted for by models of cosmic chemical evolution able to destroy in situ Deuterium due to the fragility of this isotope.
    Monthly Notices of the Royal Astronomical Society 03/2012; 426(2). DOI:10.1111/j.1365-2966.2012.21703.x · 5.11 Impact Factor
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