发表机构
Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University; Research Center for Nuclear Physics, Osaka University; Nagoya University; Advanced Science Research Center, Japan Atomic Energy Agency（名古屋大学小林诚-益川敏英粒子与宇宙起源研究所; 大阪大学核物理研究中心; 名古屋大学; 日本原子能机构先进科学研究中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
基于HAL QCD格点数据，采用重介子手征微扰论研究$DD^*$系统双π交换势，通过色散关系分离长程贡献，调节未知耦合参数再现格点结果，并预言其他$D^{(*)}$势的双π交换尾部。
AI 中文摘要
受近期HAL QCD格点结果在接近物理点 $m_\pi=146.4$ MeV 处 $D$-$D^*$ 势的启发，我们从理论上检验了 $DD^*$ 系统（半）长程部分中双π交换的效应。我们采用重介子手征微扰论框架，并考虑重夸克自旋对称性。计及了直到次次领头阶（N$^2$LO）的π交换。为了分离（半）长程贡献，我们将色散关系方法应用于单圈图。结果发现，通过调节未知的 $O(p^2)$ 耦合常数，可以再现 $0.5\\,{\rm fm} \lesssim r$ 区域内的格点 $D$-$D^*$ 势数据。特别地，同位旋无关的N$^2$LO三角形图贡献在再现 $1.0\\,{\rm fm} \lesssim r\lesssim 2.0\\,{\rm fm}$ 区域内 $V^{DD^*}\sim \left({\rm e}^{-m_\pi r}/r\right)^2$ 形式的格点数据中起核心作用。我们还给出了其他 $D^{(*)}$-$D^{(*)}$ 势的预言，其中预测了类似的双π交换尾部。我们的发现为聚焦于双π交换的 $D$-$D^*$ 势（半）长程区域提供了有用信息。
英文摘要
Motivated by the recent HAL QCD lattice results on the $D$ - $D^*$ potential at nearly physical point $m_π=146.4$ MeV, we theoretically examine effects from the two-pion exchange in (semi-)long-range parts of the $DD^*$ system. We employ the framework of heavy-meson chiral perturbation theory with heavy-quark spin symmetry. The pion exchanges up to next-to-next-to-leading order (N$^2$LO) are taken into account. In order to separate the (semi-)long-range contributions, we apply the dispersion-relation method to one-loop diagrams. As a result, we find that the lattice data on the $D$ - $D^*$ potential in the regime of $0.5\, {\rm fm} \lesssim r$ is reproduced by adjusting the unknown $O(p^2)$ couplings. In particular, it turns out that contributions from isospin-independent N$^2$LO triangle diagrams play a central role in reproducing the lattice data of the form $V^{DD^*}\sim \left({\rm e}^{-m_πr}/r\right)^2$ in $1.0\, {\rm fm} \lesssim r\lesssim 2.0\, {\rm fm}$. We also present predictions of other $D^{(*)}$ - $D^{(*)}$ potentials, where the similar two-pion exchange tail is predicted. Our findings provide useful information on the (semi-)long-range regime of the $D$ - $D^*$ potential focusing on two-pion exchanges.
Comments19 pages, 10 figures
