论文标题
新D（P，γ）HE3速率对大爆炸核合成的影响
The Impact of New d(p,γ)He3 Rates on Big Bang Nucleosynthesis
论文作者
论文摘要
我们考虑了$ d（p，γ）{}^3 $ he the luna Collaboration的新测量结果对大爆炸核合成（BBN）的影响。这些对d/h的原始丰度具有重要影响，这也对BBN时的重子密度敏感。我们使用了世界平均截面数据来重新评估了该反应的热速率，我们用模型无关的多项式描述了该反应的平均值。我们的结果与Luna的类似分析非常吻合。然后，我们使用新的速率与先前的测量结果结合使用BBN和Planck宇宙微波背景（CMB）的可能性分析进行了充分的似然分析，并使用先前的测量速率进行了比较。使用旧速率的BBN和CMB测量之间的一致性非常好。 The predicted deuterium abundance at the Planck value of the baryon density was $({\rm D/H})_{\rm BBN+CMB}^{\rm old} = (2.57 \pm 0.13) \times 10^{-5}$ which can be compared with the value determined from quasar absorption systems $({\rm d/h}）_ {\ rm obs} =（2.55 \ pm 0.03）\ times 10^{ - 5} $。使用新价格，我们发现$（{\ rm d/h}）_ {\ rm bbn+cmb} =（2.51 \ pm 0.11）\ times 10^{ - 5} $。因此，当使用反应速率适合我们的数据驱动方法时，我们发现了BBN理论，氘和$ {}^4 $观察的一致性。我们还发现，新的反应数据加强了对BBN期间相对论自由度数量的约束，从而给出了有效的光中微子物种$N_ν= 2.880 \ pm 0.144 $与粒子物理的标准模型非常吻合。最后，我们注意到，观察到的氘丰度仍然比BBN+CMB预测更为精确，该预测的错误预算现在以$ d（d，n）{}^3 $ He和$ d（d，p）{} {}^{3} {3} {\ rm H} $主导。
We consider the effect on Big Bang Nucleosynthesis (BBN) of new measurements of the $d(p,γ){}^3$He cross section by the LUNA Collaboration. These have an important effect on the primordial abundance of D/H which is also sensitive to the baryon density at the time of BBN. We have re-evaluated the thermal rate for this reaction, using a world average of cross section data, which we describe with model-independent polynomials; our results are in good agreement with a similar analysis by LUNA. We then perform a full likelihood analysis combining BBN and Planck cosmic microwave background (CMB) likelihood chains using the new rate combined with previous measurements and compare with the results using previous rates. Concordance between BBN and CMB measurements of the anisotropy spectrum using the old rates was excellent. The predicted deuterium abundance at the Planck value of the baryon density was $({\rm D/H})_{\rm BBN+CMB}^{\rm old} = (2.57 \pm 0.13) \times 10^{-5}$ which can be compared with the value determined from quasar absorption systems $({\rm D/H})_{\rm obs} = (2.55 \pm 0.03) \times 10^{-5} $. Using the new rates we find $({\rm D/H})_{\rm BBN+CMB} = (2.51 \pm 0.11) \times 10^{-5}$. We thus find consistency among BBN theory, deuterium and ${}^4$He observations, and the CMB, when using reaction rates fit in our data-driven approach. We also find that the new reaction data tightens the constraints on the number of relativistic degrees of freedom during BBN, giving the effective number of light neutrino species $N_ν= 2.880 \pm 0.144$ in good agreement with the Standard Model of particle physics. Finally, we note that the observed deuterium abundance continues to be more precise than the BBN+CMB prediction, whose error budget is now dominated by $d(d,n){}^3$He and $d(d,p){}^{3}{\rm H}$.
