Lattice Gauge Theory at the Intensity Frontier

该奖项为犹他州大学的卡尔顿·德塔尔教授的研究活动提供资金。 deTar教授的研究解决了高能物理和核物理中的基本问题，并且与这些领域的主要实验项目密切相关。 这项研究的主要目标是发现新的基本物理过程和粒子的证据。 这是通过将目前已知的物理过程和粒子的理论的精确预测与精确实验的结果进行比较来完成的。 deTar教授和他的合作者开发的方法及其计算产品和软件在世界各地广泛用于相关研究。 除了保持美国在基础科学方面的优势外，这项研究还支持美国在计算技术和人力方面的优势。 从事这些项目的学生和博士后研究人员在高性能计算和最先进的大型数据集统计分析方面接受了非常有市场的培训。 在更专业的术语中，deTar教授和他的合作者正在量子色动力学（QCD），夸克和胶子相互作用的理论方面进行广泛的研究计划。 他们在高性能计算机上使用数值计算来完成这一过程。 这些数值计算是在时空点的网格（格子）上完成的。 在过去的几年里，他们已经产生了一个库的胶子配置合奏与上，下，奇怪和魅力夸克，使用高度改进的交错夸克（HISQ）的行动。 这些胶子组态可以被认为是QCD真空的“快照”，并且是各种物理计算的基础。 这些集合具有比它们先前使用改进的交错（asqtad）动作生成的那些明显更小的晶格伪影。 此外，这些计算已经达到了一个重要的里程碑，第一次产生了四个最轻的夸克都包含在质量等于或非常接近其物理值的配置。 由于这些原因，HISQ系综使高能物理中各种重要物理量的计算得到重大改进，包括对μ子磁矩的强相互作用贡献。 这些标准模型预测的结果将与费米实验室目前正在进行的实验测量进行核对。 deTar教授和他的合作者还在扩展他们对π、K、D、Ds、B和Bs介子的轻子衰变常数、D和B介子的半轻子形状因子以及中性B和Bs介子与其反粒子的混合的研究。 这些计算将使他们能够显著提高Cabibbo-Kobayashi-Maskawa（CKM）矩阵元V_us、V_ub、V_cd、V_cs和V_cb以及上、下、奇、魅和底夸克质量的测定精度。 CKM矩阵元的计算将为我们现有的物理学基本相互作用理论提供更严格的检验，而相关强子弱相互作用矩阵元的确定可以帮助约束已经提出来研究超出我们现有理论的物理学的理论。

This award funds the research activities of Professor Carleton DeTar at the University of Utah. Professor deTar's research addresses fundamental questions in high-energy and nuclear physics, and is closely related --- indeed, even essential --- to major experimental programs in these fields. The principal goal of this research is to discover evidence for new fundamental physical processes and particles. This is done by comparing precise predictions of theories of currently known physical processes and particles with the results of precise experiments. The methods that Professor deTar and his collaborators develop and their calculational products and software are used widely around the world for related studies. In addition to maintaining US excellence in fundamental science, this research supports US preeminence in computing technology and manpower. Students and postdoctoral research associates working on these projects receive highly marketable training in high-performance computing and state-of-the-art statistical analysis of large data sets. In more technical terms, Professor deTar and his collaborators are carrying out a broad research program in Quantum Chromodynamics (QCD), the theory of interacting quarks and gluons. They do this using numerical calculations on high-performance computers. These numerical calculations are done on a grid of space-time points (lattice). During the last several years they have generated a library of gluon-configuration ensembles with up, down, strange and charm quarks, using the highly improved staggered quark (HISQ) action. These gluon configurations can be thought of as "snapshots" of the QCD vacuum, and are the basis for a wide variety of calculations of physical interest. These ensembles have significantly smaller lattice artifacts than those they previously generated with the improved staggered (asqtad) action. Moreover, these calculations have reached an important milestone by generating, for the first time, configurations in which the four lightest quarks are all included with masses at or very close to their physical values. For these reasons the HISQ ensembles are enabling major improvements in the calculation of a variety of physical quantities of importance in high-energy physics, including the strong-interaction contributions to the magnetic moment of the muon. Results of these Standard-Model predictions will be checked against experimental measurements currently underway at Fermilab. Professor deTar and his collaborators are also extending their studies of the leptonic decay constants of the pi, K, D, Ds, B and Bs mesons, the semileptonic form factors of D and B mesons, and the mixing of neutral B and Bs mesons with their antiparticles. These calculations will enable them to significantly improve the precision of their determinations of the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements V_us, V_ub, V_cd, V_cs, and V_cb, as well as the masses of the up, down, strange, charm and bottom quarks. The calculations of the CKM matrix elements will provide more stringent tests of our current theories of the fundamental interactions of physics, while the determination of related hadronic weak-interaction matrix elements can help constrain theories that have been proposed to study physics that goes beyond our current theories.