QCD Sum Rules and Hadronic Matrix Elements

QCD 求和规则和强子矩阵元素

• 批准号: 230799646
• 负责人: Professor Dr. Alexander Khodjamirian
• 金额: --
• 依托单位: Department Physik
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2012
• 资助国家: 德国
• 起止时间: 2011-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/230799646?language=en
• 关键词: QCD; Sum; Rules; Hadronic; Matrix

In contemporary particle physics research, the fundamental transitions between quarks with different flavour quantum numbers are being intensively investigated in exclusive semileptonic and radiative decays of hadrons containing heavy b- or c-quarks. These processes are especially interesting because they are sensitive to virtual effects of new heavy particles beyond the Standard Model of particle physics. In studies of heavy hadron decays, the theoretical accuracy has to match the high precision of the experimental measurements (at the “Large Hadron Collider” and at future accelerator facilities, the so called “super-flavour factories”). Here, the main challenge lies in the theoretical computation of the strong-interaction effects in Quantum Chromodynamics (QCD). In this project, a combination of theoretical methods aimed at solving this problem will be further developed and applied.The emphasis will be on the so-called light-cone sum rule approach in QCD. Based on analytical calculations, the sum-rule method combines several powerful theory tools: the operator-product expansion in QCD, hadronic dispersion relations and quark-hadron duality. The calculational procedures in QCD will be supplemented by systematic expansions of hadronic amplitudes in QCD-based effective theories, such as the Soft-Collinear Effective Theory. We plan new applications of the sum-rule technique, including: the calculation of semileptonic B- and D-meson decay amplitudes with two pseudoscalar mesons in the final state, the semileptonic transitions of heavy baryons, and the hadronic matrix elements relevant for heavy-hadron decays with flavour-changing neutral currents. In addition to the conventional light-cone sum rules, new sum rules in the effective theories will be obtained to assess the effects of the resummation of higher-order effects in the operator-product expansion.

在当代粒子物理研究中，具有不同风味量子数的夸克之间的基本转变正在包含重 b 或 c 夸克的强子的专有半轻子和辐射衰变中得到深入研究。这些过程特别有趣，因为它们对超出粒子物理标准模型的新重粒子的虚拟效应敏感。在重强子衰变的研究中，理论精度必须与实验测量的高精度相匹配（在“大型强子对撞机”和未来的加速器设施，即所谓的“超级工厂”）。这里的主要挑战在于量子色动力学（QCD）中强相互作用效应的理论计算。在这个项目中，旨在解决这个问题的理论方法组合将得到进一步发展和应用。重点将放在QCD中所谓的光锥和法则方法上。基于解析计算，和律方法结合了几种强大的理论工具：QCD 中的算子乘积展开式、强子色散关系和夸克-强子对偶性。 QCD 的计算程序将通过基于 QCD 的有效理论（例如软共线有效理论）中强子振幅的系统扩展来补充。我们计划了求和法则技术的新应用，包括：计算最终状态下两个赝标量介子的半轻B介子和D介子衰变幅度、重重子的半轻子跃迁，以及与改变味道的中性电流的重强子衰变相关的强子矩阵元素。除了传统的光锥和规则外，还将获得有效理论中新的和规则，以评估算子-乘积展开中高阶效应恢复的效果。