发表机构
Universität Siegen（锡根大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文发展了一种基于软-共线有效理论的有效强子理论，用于大反冲下B到π衰变形状因子，并计算了其单圈手征对数修正，发现与硬-π手征微扰理论结果不一致。
AI 中文摘要
我们发展了一种有效的强子理论，用于描述重介子衰变为高能π介子的过程，该理论基于近似的重夸克对称性和手征对称性组织。该理论的动力学自由度包括准静态重介子场，它们与软π介子和共线π介子耦合，适用于大反冲能量 ${E_\pi \simeq M_B/2}$ 下的排他性 $B \to \pi$ 跃迁。我们的方法利用了软-共线有效理论（SCET）中软夸克和共线夸克的可因子化性，导致在两个运动学扇区中出现手征对称性的倍增。将软和共线手征变换提升为局域对称性，使我们能够系统地将SCET中的非局域四夸克算符（控制重到轻形状因子的软重叠贡献）匹配到由手征对称性破缺标度以下的强子场构成的有效算符上。作为首次应用，我们通过计算领先强子算符的单圈矩阵元，计算了 $B \to \pi$ 形状因子在大反冲下对数增强的π介子质量依赖性。我们发现，我们有效理论中的非局域跃迁流导致的手征对数修正模式与现有硬-π手征微扰理论给出的表述不相容。
英文摘要
We develop an effective hadronic theory for heavy-meson decays into energetic pions, organized by the approximate heavy-quark and chiral symmetries. The dynamical degrees of freedom of the theory consist of quasi-static heavy-meson fields coupled to soft and collinear pions, relevant for exclusive $B \to π$ transitions at large recoil energy ${E_π\simeq M_B/2}$. Our approach exploits the factorization of soft and collinear quarks in Soft-Collinear Effective Theory (SCET), leading to an emergent duplication of chiral symmetry in the two kinematic sectors. Promoting the soft and collinear chiral transformations to local symmetries enables us to systematically match non-local four-quark operators in SCET -- governing the soft-overlap contribution to heavy-to-light form factors -- onto effective operators constructed from hadronic fields below the scale of chiral symmetry breaking. As a first application, we compute the logarithmically enhanced pion-mass dependence of the $B \to π$ form factors at large recoil by calculating the one-loop matrix elements of the leading hadronic operators. We find that the non-local transition currents in our effective theory lead to a pattern of chiral-logarithmic corrections that is not compatible with the existing formulation provided by Hard-Pion Chiral Perturbation Theory.
Comments31 pages, 4 figures
