The decay of 50.0 min<sup>98m</sup>Nb

Singh, B.; Tivin, P.J.; Taylor, H.W.

doi:10.1088/0305-4616/2/2/006

Cited by 6 publications

(5 citation statements)

References 11 publications

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“…At the WMAP-measured value of the baryon-to-photon ratio η b , more than 90% of the primordial lithium is produced in the form of 7 Be in the radiative capture process, 4 He+ 3 He→ 7 Be+γ. The output of 7 Be is almost linearly dependent on the corresponding S-factor for this reaction, which was recently re-measured by several groups [36,37,38]. The current ∼15% accuracy prediction for the combined 7 Be+ 7 Li abundance stands at [22] SBBN :…”

Section: Sbbnmentioning

confidence: 92%

Big Bang Nucleosynthesis as a Probe of New Physics

Pospelov

Pradler

2010

Annu. Rev. Nucl. Part. Sci.

222

253

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Big bang nucleosynthesis (BBN), an epoch of primordial nuclear transformations in the expanding Universe, has left an observable imprint in the abundances of light elements. Precision observations of such abundances, combined with high-accuracy predictions, provide a nontrivial test of the hot big bang and probe non-standard cosmological and particle physics scenarios. We give an overview of BBN sensitivity to different classes of new physics: new particle or field degrees of freedom, time-varying couplings, decaying or annihilating massive particles leading to non-thermal processes, and catalysis of BBN by charged relics.Comment: 37 pages, 9 figure

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Section: Sbbnmentioning

confidence: 92%

Big Bang Nucleosynthesis as a Probe of New Physics

Pospelov

Pradler

2010

Annu. Rev. Nucl. Part. Sci.

222

253

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“…As the rate for this process per each 3 He nucleus is much slower than the Hubble rate, the output of 7 Be is almost linearly dependent on the corresponding S-factor for this reaction. With recent improvement in its experimental determination [8,9,10], the current ∼15% accuracy prediction for 7 Be+ 7 Li stands at 5.24 +0. 71 −0.67 × 10 −10 [7].…”

Section: Standard Bbn -Theorymentioning

confidence: 99%

“…This results in O(10 −14 ) level prediction for primordial 6 Li which is well below the detection capabilities. Heavier elements with A ≥ 9 such as 9 Be, 10 B and 11 B are never made in any significant quantities in the SBBN framework, and the main reason for that is the absence of stable A = 8 nuclei, as 8 Be is underbound by 92 keV and decays to two α.…”

Section: Standard Bbn -Theorymentioning

confidence: 99%

Big Bang nucleosynthesis and particle dark matter

2009

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Following a recent suggestion of axion cooling of photons between the nucleosynthesis and recom-bination epochs in the Early Universe, we investigate a hybrid model with both axions and relic supersymmetric particles. In this model we demonstrate that the 7 Li abundance can be consistent with observations without destroying the important concordance of deuterium abundance. PACS numbers: 26.35.+c, 98.80.Cq, 98.80.Es, 98.80.Ft Introduction-Low-metallicity halo stars exhibit a plateau of 7 Li abundance, indicating the primordial origin of 7 Li [1]. However, the amount of 7 Li needed to be consistent with the cosmic microwave background observations [2] is significantly more than 7 Li observed in old halo stars [3]. (Even though 7 Li can be both produced and destroyed in stars, old halo dwarf stars are expected to have gone through little nuclear processing). Recent improvements in the observational and experimental data seem to make the discrepancy worse [4, 5]. One possible solution is to invoke either nuclear physics hitherto excluded from the Big-Bang Nucleosynthesis (BBN) [6, 7] or new physics such as variations of fundamental couplings [8, 9], and particles not included in the Standard Model [10-42]. Effects of massive neutral relic particles on BBN were extensively studied [10-28].

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“…Some uncertainty remains in the adopted stellar atmospheric temperatures, which may lead to somewhat higher estimates, as in the case of the globular cluster NGC 6397 7 Li/H = 2.19 ± 0.28 × 10 −10 [24,25] or the somewhat controversial result 7 Li/H= (2.34±0.32)×10 −10 ( [26]) for a sample of halo field stars. This is to be compared to the most recent standard BBN prediction of 7 Li/H = (5.24 +0.71 −0.67 ) × 10 −10 [27] taking into account experimental re-evaluations of the for the 7 Li abundance most important 3 He(α, γ) 7 Be reaction rate [28,29,30,31]. Renewed measurements of this rate has not only increased the central value for 7 Li/H by around 25% , but also reduced its error bar considerably, thereby leaving the discrepancy between prediction and observation more pronounced (around 4.2-5.3σ [27]).…”

Section: Introductionmentioning

confidence: 99%

“…7. Finally, the re-evaluation of the main 7 Li producing rate [27,28,29,30,31], as well as a shift in Ω b h 2 [18], as indicated in the introduction, has increased the predicted standard BBN 7 Li abundance. These changes are included in the present paper as well as recent changes in some catalytic rections rates [66].…”

Section: Introductionmentioning

confidence: 99%

Gravitino dark matter and the cosmic lithium abundances

2009

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Supersymmetric extensions of the standard model of particle physics assuming the gravitino to be the lightest supersymmetric particle (LSP), and with the next-to-LSP decaying to the gravitino during Big Bang nucleosynthesis, are analyzed. Particular emphasis is laid on their potential to solve the " 7 Li problem", an apparent factor 2 − 4 overproduction of 7 Li in standard Big Bang nucleosynthesis (BBN), their production of cosmologically important amounts of 6 Li, as well as the resulting gravitino dark matter densities in these models. The study includes several improvements compared to prior studies concerning NLSP hadronic branching ratios, NLSP dark matter densities, the evaluation of hadronic NLSP decays on BBN, BBN catalytic effects, as well as updated nuclear reaction rates. Heavy gravitinos in the constrained minimal supersymmetric standard model (CMMSM) are reanalyzed, whereas light gravitinos in gauge-mediated supersymmetry breaking scenarios (GMSB) are studied for the first time. It is confirmed that decays of NLSP staus to heavy gravitinos, while producing all the dark matter, may at the same time resolve the 7 Li problem. For NLSP decay times ≈ 10 3 sec, such scenarios also lead to cosmologically important 6 Li (and possibly 9 Be) abundances. However, as such scenarios require heavy > ∼ 1 TeV staus they are likely not testable at the LHC. It is found that decays of NLSP staus to light gravitinos may lead to significant 6 Li (and 9 Be) abundances, whereas NLSP neutralinos decaying into light gravitinos may solve the 7 Li problem. Though both scenarios are testable at the LHC they may not lead to the production of the bulk of the dark matter. A section of the paper outlines particle properties required to significantly reduce the 7 Li abundance, and/or enhance the 6 Li (and possibly 9 Be) abundances, by the decay of an arbitrary relic particle.

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The decay of 50.0 min^98mNb

Cited by 6 publications

References 11 publications

Big Bang Nucleosynthesis as a Probe of New Physics

Big Bang Nucleosynthesis as a Probe of New Physics

Big Bang nucleosynthesis and particle dark matter

Gravitino dark matter and the cosmic lithium abundances

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The decay of 50.0 min98mNb

Cited by 6 publications

References 11 publications

Big Bang Nucleosynthesis as a Probe of New Physics

Big Bang Nucleosynthesis as a Probe of New Physics

Big Bang nucleosynthesis and particle dark matter

Gravitino dark matter and the cosmic lithium abundances

Contact Info

Product

Resources

About

The decay of 50.0 min^98mNb