从壳振幅构建的有效场论中的氘生成
Deuterium Production in an Effective Field Theory Constructed from On-Shell Amplitudes
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中文总结 AI 辅助
该研究构建从壳振幅出发的有效场论计算氘生成反应，经贝叶斯拟合确定热核反应率，降低了原初氘丰度预测的不确定度。
中文摘要 AI 辅助
我们在一种有效场论中计算氘生成反应$n+p \to d+\boldsymbol{\u03b3}$，该理论的自由度为核态本身：振幅由壳三点顶点组装，跨其因式分解通道拼接，并补充符合对称性的接触项。氘通过$d$-$n$-$p$顶点引入，该顶点归一化至测得的渐近归一化系数。核子对的再散射通过色散方式重求和，仅留下两个短程常数：同位矢量磁偶极和电偶极接触相互作用。对热俘获测量与SLEGS光致解离数据的联合贝叶斯拟合发现，这两个常数均为自然量级，且确定了核合成窗口内的热核反应率为0.22-0.24%，其中包含对SLEGS数据和P波再散射的合理处理所带来的系统误差。展开截断的单独边界为0.12%，其中接触项的下一阶（与两个拟合常数简并）贡献0.03%，总理论不确定度为0.25-0.27%。通过大爆炸核合成（BBN）网络传播后，该反应率使预测的原初氘丰度偏移-0.06%，并将该反应对D/H不确定度的贡献从0.089%降至0.050%，实际上将其从原初D/H误差预算中剔除。
英文摘要
We compute the deuterium-production reaction $n+p \to d+γ$ in an effective field theory whose degrees of freedom are the nuclear states themselves: the amplitude is assembled from on-shell three-point vertices, glued across its factorization channels, and completed by the contact terms consistent with the symmetries. The deuteron enters through the $d$-$n$-$p$ vertex, normalized to the measured asymptotic normalization coefficient. Rescattering of the nucleon pair is resummed dispersively, leaving two short-distance constants, an isovector magnetic and an electric dipole contact interaction. A joint Bayesian fit to the thermal capture measurements and the SLEGS photodisintegration data finds both of natural size and determines the thermonuclear rate to 0.22-0.24% across the nucleosynthesis window, including systematics spanning the defensible treatments of the SLEGS data and of the $P$-wave rescattering. Truncating the expansion is bounded separately at 0.12%, of which the next order of contact terms -- degenerate with the two fitted constants -- supplies 0.03%, for a total theory uncertainty of 0.25-0.27%. Propagated through a BBN network, the rate shifts the predicted primordial deuterium by -0.06% and cuts this reaction's contribution to the D/H uncertainty from 0.089% to 0.050%, retiring it from the primordial D/H error budget for practical purposes.
