High-precision lattice QCD for standard and nonstandard model physics

该资助旨在研究物质的夸克和胶子结构。夸克和胶子是强子（字面意思是“强相互作用粒子”）的基本组成部分，比如质子和中子。夸克和胶子相互作用的完整理论称为量子色动力学（QCD）。我们有信心QCD是正确的，因为理论技术允许精确计算某些过程，例如强子之间的高能碰撞。然而，要可靠地计算强子的低能性质，如它们的质量和衰变率，要困难得多，因为唯一可用的技术（所谓的晶格QCD）需要在非常大的计算机集群上进行数值模拟。直到最近，即使在最大的计算机集群上也不可能进行足够精确的格点QCD模拟。幸运的是，最近的理论发展已经大大减少了所需的计算机能力。我在过去几年的工作，作为HPQCD合作的一部分，一群美国的理论家，加拿大和英国，已经导致了几个高影响力的测试和预测的理论，在前所未有的精度水平。为了充分利用这些新的理论发展，还需要做更多的工作，这是拟议研究计划的主题。这项工作很重要，因为它将对解释可能揭示新物理现象的实验产生重大影响。为了正确解释这些实验结果，通常需要晶格QCD模拟的结果。在这项资助下要做的工作集中在理论分析的一些关键要素上，这些要素是正确使用和解释数值模拟结果所必需的，并将继续参与我的SFU研究小组与HPQCD的合作。

This grant is directed towards the study of the quark and gluon substructure of matter. Quarks and gluons are the elementary constituents of hadrons (literally, "strongly-interacting particles") such as the proton and neutron. The complete theory of quark and gluon interactions is called Quantum Chromodynamics (QCD). We have confidence that QCD is correct because of theoretical techniques that permit accurate calculations of certain processes, such as those involving high-energy collisions between hadrons. However it is much more difficult to reliably calculate low-energy properties of hadrons, such as their masses and decay rates, because the only available technique (so-called lattice QCD) requires numerical simulations on very large computer clusters. Until recently it was not possible to do lattice QCD simulations of sufficient precision even on the largest available computer clusters. Fortunately, recent theoretical developments have dramatically reduced the amount of computer power that is required. My work over the past few years, as part of the HPQCD collaboration, a group of theorists in the U.S., Canada, and the U.K., has resulted in several high-impact tests and predictions of the theory, at a heretofore unprecedented level of precision. Much additional work is required in order to fully exploit these new theoretical developments, and this is the subject of the proposed research program. This work is important because it will have a strong bearing on the interpretation of experiments which may reveal new physical phenomena. The results of lattice QCD simulations are generally required in order to properly interpret the results of these experiments. The work to be done under this grant is centered on some key elements of the theoretical analysis that is needed in order to properly use and interpret the results of the numerical simulations, and will continue the involvement of my SFU research group with the HPQCD collaboration.