标题： 新d(p,γ)He3反应率对大爆炸核合成的影响 显示英文标题

标题： The Impact of New d(p,γ)He3 Rates on Big Bang Nucleosynthesis

摘要： 我们考虑了LUNA合作组对$d(p,\gamma){}^3$氦核截面的新测量对大爆炸核合成（BBN）的影响。这些测量对原始氘氢比有重要影响，而该比值也对BBN发生时的重子密度敏感。我们使用截面数据的世界平均值重新评估了该反应的热速率，我们用与模型无关的多项式来描述这些数据；我们的结果与LUNA的类似分析一致。然后，我们进行了完整的似然分析，结合BBN和普朗克宇宙微波背景（CMB）似然链，使用新速率结合之前的数据，并与使用旧速率的结果进行比较。使用旧速率时，BBN和CMB对各向异性谱的测量之间有很好的一致性。在普朗克重子密度值下预测的氘丰度为$({\rm D/H})_{\rm BBN+CMB}^{\rm old} = (2.57 \pm 0.13) \times 10^{-5}$，可以与通过类星体吸收系统确定的值$({\rm D/H})_{\rm obs} = (2.55 \pm 0.03) \times 10^{-5} $进行比较。使用新速率，我们发现$({\rm D/H})_{\rm BBN+CMB} = (2.51 \pm 0.11) \times 10^{-5}$。因此，当使用我们在数据驱动方法中拟合的反应速率时，BBN理论、氘和${}^4$氦观测以及CMB之间是一致的。我们还发现，新的反应数据收紧了BBN期间相对论自由度数量的约束，给出了有效轻中微子种类数$N_\nu = 2.880 \pm 0.144$，这与粒子物理的标准模型相符。 最后，我们注意到观测到的氘丰度仍然比BBN+CMB预测更精确，其误差预算现在主要由$d(d,n){}^3$He和$d(d,p){}^{3}{\rm H}$主导。 显示英文摘要

摘要： We consider the effect on Big Bang Nucleosynthesis (BBN) of new measurements of the $d(p,\gamma){}^3$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 $N_\nu = 2.880 \pm 0.144$ 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 $d(d,p){}^{3}{\rm H}$.