AI 中文总结
利用泛函重整化群方法中的大动量有效理论，对π介子分布振幅进行首次泛函量子色动力学计算，仅以强耦合和流夸克质量为输入，从第一性原理量子色动力学关联函数计算准分布振幅，其结果与其他非微扰方法一致。
AI 中文摘要
我们展示了使用泛函重整化群（fRG）方法中的大动量有效理论对π介子分布振幅（DA）进行的首次泛函量子色动力学计算。仅将强耦合和流夸克质量作为输入，我们从第一性原理量子色动力学关联函数计算准DA。通过将π介子动量提高到\(P_z = 4.5\ \mathrm{GeV}\)，准DA变得完全饱和，使得向光锥极限的外推误差可忽略不计。得到的二阶矩\(\langle \xi^2 \rangle_\pi = 0.267\)明显小于现有的晶格 - LaMET测定值，并且处于与其他非微扰方法一致的范围内。
英文摘要
We present the first functional QCD calculation of the pion distribution amplitude (DA) using the large-momentum effective theory within the functional renormalisation group (fRG) approach. With only the strong coupling and current quark masses as inputs, we compute the quasi-DA from first-principles QCD correlation functions. By pushing the pion momentum up to $P_z = 4.5\ \mathrm{GeV}$, the quasi-DA becomes fully saturated, rendering the extrapolation errors to the light-cone limit negligible. The resulting second-order moment $\langle ξ^2 \rangle_π= 0.267$ is significantly smaller than existing lattice-LaMET determinations and lies in a range consistent with other nonperturbative approaches.
Comments17 pages, 11 figures, 2 tables; v2: Added references and corrected minor typos
