Lattice QCD Study of Hadron Excitations Using All-to-All Quark Propagators with Improved Variance Reduction

使用具有改进方差减少的全夸克传播器进行强子激发的晶格 QCD 研究

• 批准号: 0969863
• 负责人: Colin Morningstar
• 金额: $ 56.4万
• 依托单位: Carnegie-Mellon University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0969863&HistoricalAwards=false
• 关键词: Lattice; QCD; Study; Hadron; Excitations

The masses of excited hadron resonances will be evaluated using computer simulations of quarks and gluons on a space-time lattice. These resonance states are being studied in several experiments, such as in the Hall B N* program and the GlueX experiment in Hall D at the Thomas Jefferson National Accelerator Facility. Such systems should also provide a wealth of information to help us understand the physics of quark confinement and hadron formation in quantum chromodynamics, the theory of the strong interactions and one of the fundamental forces of Nature. Understanding the physics of confining gluons is an important intellectual challenge; in fact, it is one of the seven so-called Millenium Prize problems announced by the Clay Mathematics Institute of Cambridge, Massachusetts. One of the most reliable means of investigating such systems is using Markov-chain Monte Carlo computations with quark and gluon fields defined on a space-time lattice. In the past, such calculations have been done with unrealistically large quark masses due to computational limitations. Current calculations have reduced the quark masses to nearly their physical values, causing the need to incorporate multi-hadron operators into the computations to become crucial. A new methodology for dealing with multi-hadron operators has been developed in the recent past, and this proposal plans to apply the new methodology to carry out the first calculations of the hadron masses using both single and multi-hadron operators. The proposed research incorporates the participation of two graduate students, and possibly one or more undergraduate students, whose educations will be enhanced not only by involvement in scientific projects at the forefront of nuclear theory, but also with high-technology training in the use of state-of-the-art parallel computing resources. The broader impacts of the proposed activities will be strengthened by posting results with simplified background information on publicly accessible web pages.

将使用时空晶格上的夸克和胶子的计算机模拟来评估激发强子共振的质量。 这些共振状态正在进行多个实验中，例如在托马斯·杰斐逊国家加速器设施的霍尔D厅的B n*计划和Gluex实验中。 这样的系统还应提供大量信息，以帮助我们了解量子染色体动力学中夸克限制和强子形成的物理学，强烈相互作用的理论以及自然的基本力量之一。 了解限制振荡的物理学是一个重要的智力挑战。实际上，这是马萨诸塞州剑桥克莱数学研究所宣布的七个所谓的千年奖问题之一。 调查此类系统的最可靠手段之一是使用Markov-Chain Monte Carlo计算与时空晶格上定义的夸克和Gluon场。 过去，由于计算限制，这种计算是用不切实际的夸克质量进行的。 当前的计算将夸克质量降低到其几乎的物理价值，从而导致需要将多 - 戴隆运算符纳入计算以变得至关重要。 最近，已经开发了一种与多 - 戴隆操作员打交道的新方法，该提案计划应用新方法，以使用单个和多 - 戴隆操作员同时对强子进行第一个计算。 拟议的研究结合了两名研究生的参与，甚至可能是一名或多个本科生，他们的教育将不仅通过参与核理论最前沿的科学项目，而且还通过高技术培训来增强教育，并在使用先进的平行计算资源中使用高科技培训。 通过在公开访问的网页上发布简化的背景信息，将加强拟议活动的更广泛影响。