Three-Body Amplitudes from Lattice QCD

晶格 QCD 的三体振幅

• 批准号: 2310036
• 负责人: Michael Doering
• 金额: $ 36万
• 依托单位: George Washington University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2310036&HistoricalAwards=false
• 关键词: Three; Body; Amplitudes; Lattice; QCD

Strong forces are responsible for the formation of known matter in the Universe, but the detailed mechanisms of how this happens remain a mystery. Strong forces bind nucleons (protons and neutrons) together in atomic nuclei, and the properties of the nucleons are studied at state-of-the-art accelerator facilities such as the Thomas Jefferson National Accelerator Facility. This project aims at closing the gap between experiment and theoretical calculations using lattice QCD. Due to current limitations of classical computers Lattice QCD calculations are performed in a small cubic volume instead of infinite space. This project provides the translation from the former to the latter, so that fundamental calculations of QCD can be compared to Nature. The PI and his students will focus on properties of systems involving three particles interacting with each other. To help develop a diverse, globally competitive STEM workforce, the outreach component is dedicated to developing material for computational aspects of quantum mechanics (QM) and animations of time-dependent QM problems. Finite-volume effects for the case of three particles are poorly understood. In this project, the PI and his students will develop and apply three-body methods to map lattice QCD results to the physical world and to help answer fundamental questions regarding QCD predictions for the properties of excited mesons and baryons. For this, the principle of unitarity is efficiently used as the guiding principle to construct three- or more particle amplitudes. A conceptual upgrade of previous work concerns the introduction of more coupled channels and extensions to half-integer spin. Three-body dynamics is not only difficult on the theory but also on the phenomenology side. Therefore, three-body amplitudes in infinite volume will be developed and compared to experiment in a complementary effort, such as the Roper resonance and its multi-channel three-body dynamics, or the various decay channels of the A1(1260) axial meson. An extended analysis of new lattice QCD results from the GW group at two different pion masses is planned, that will allow to map out the chiral trajectory of the A1(1260) axial meson.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

强大的力量负责宇宙中已知物质的形成，但这种情况如何发生的详细机制仍然是个谜。强大的力量将原子核中的核子（质子和中子）束缚在一起，核子的特性在托马斯·杰斐逊国家加速器设施等最先进的加速器设施中进行研究。该项目旨在利用晶格 QCD 缩小实验与理论计算之间的差距。由于当前经典计算机的限制，格子 QCD 计算是在小立方体积而不是无限空间中进行的。该项目提供了从前者到后者的转换，以便 QCD 的基本计算可以与自然进行比较。 PI 和他的学生将重点研究涉及三个粒子相互作用的系统的特性。为了帮助培养一支多元化、具有全球竞争力的 STEM 劳动力队伍，外展部分致力于开发量子力学 (QM) 计算方面的材料以及与时间相关的 QM 问题的动画。对于三个粒子情况的有限体积效应知之甚少。在这个项目中，PI和他的学生将开发并应用三体方法将晶格QCD结果映射到物理世界，并帮助回答有关激发介子和重子特性的QCD预测的基本问题。为此，幺正性原理被有效地用作构建三个或更多粒子振幅的指导原则。先前工作的概念升级涉及引入更多耦合通道和半整数自旋的扩展。 三体动力学不仅在理论上困难，而且在现象学方面也困难。因此，将开发无限体积中的三体振幅，并与互补的实验进行比较，例如罗珀共振及其多通道三体动力学，或A1(1260)轴向介子的各种衰变通道。计划对 GW 小组在两个不同 π 质量下的新晶格 QCD 结果进行扩展分析，这将能够绘制出 A1(1260) 轴向介子的手性轨迹。该奖项反映了 NSF 的法定使命，并被认为是值得的通过使用基金会的智力优势和更广泛的影响审查标准进行评估来提供支持。