Lattice Gauge Theory at the Intensity Frontier

该奖项资助犹他大学卡尔顿·迪塔尔教授的研究活动。我们目前对自然界中最基本的基本粒子和相互作用的理解被封装在“标准模型”中。然而，这个理论是不完整的。例如，它不能解释弥漫在宇宙中的暗物质。因此，物理学家几乎普遍认为，还有更多的基本粒子和相互作用有待发现。为了寻找新的粒子，一项大型实验研究正在加速器上进行，比如欧洲大型强子对撞机。即使加速器的能量不足以发现它们，它们也会通过仔细测量和基于标准模型的精确理论预测之间的差异揭示它们的存在。只有当预测量的剩余不确定度随着实验测量精度的提高而减少时，这种比较才有效。DeTar教授和他的合作者正在使用最强大的计算机和代码来做出精确的预测，这些预测可以与实验测量的结果进行比较，并特别注意那些已经发现了一些诱人差异的情况。这项工作符合国家利益，因为它进一步加深了我们对自然最基本规律的理解。这项工作的更广泛的影响包括训练学生和博士后研究人员编程和使用最高性能的计算机，管理大型数据集，以及统计分析和提取物理重要信息。这种经历应该为学生和博士后研究助理在工业和学术环境中利用这些技能的工作做好准备。从技术上讲，这个多年的项目将使用数值点阵量子色动力学的方法来精确研究重夸克衰变的强子环境，特别是底夸克。所得的强子衰变常数和形状因子然后与含有这些重夸克的介子衰变的测量相结合。该项目还将计算强相互作用对μ子异常磁矩的贡献。所得的强子真空极化值将与正在进行的高精度磁矩实验测量结果进行比较。这两种比较都为标准模型的一致性提供了严格的检验，也为新物理学的理论模型提供了约束。为了使计算足够精确，现在有必要考虑虚拟光子的影响。这个项目将包括他们。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This award funds the research activities of Professor Carleton DeTar at the University of Utah.Our current understanding of the most fundamental elementary particles and interactions in Nature is encapsulated in the "Standard Model". However, this theory is incomplete. For example, it cannot explain the dark matter that permeates the Universe. Thus physicists almost universally believe that still more fundamental particles and interactions are yet to be discovered. A large experimental search is underway at accelerators, such as the European Large Hadron Collider, to find new particles. Even if the accelerator energy is not high enough to find them, they will reveal their existence through discrepancies between careful measurements and precise theoretical predictions based on the Standard Model. Such comparisons are effective only if the residual uncertainties in the predicted quantities are reduced in tandem with improvements in the accuracy of experimental measurements. Professor DeTar and his collaborators are using the most powerful computers and codes to make precise predictions that can be compared with results of experimental measurements with particular attention to those cases in which some tantalizing discrepancies have already been found. This work is in the national interest in that it furthers our understanding of the most fundamental laws of Nature. The broader impacts of this work include training students and postdoctoral research associates in programming and utilizing the highest-performance computers, in the management of large data sets, and in the statistical analysis and extraction of physically important information. This experience should prepare students and postdoctoral research associates for jobs that utilize those skills, both in industrial as well as academic settings.More technically, this multiyear project will use methods of numerical lattice quantum chromodynamics in a precision study of the hadronic environment of heavy-quark decays --- particularly the bottom quark. The resulting hadronic decay constants and form factors are then combined with measurements of the decays of mesons containing those heavy quarks. The project will also calculate the strong-interaction contribution to the anomalous magnetic moment of the muon. The resulting value for the hadronic vacuum polarization will be compared with results of ongoing high-precision experimental measurements of the magnetic moment. Both comparisons provide stringent tests of the consistency of the Standard Model and constraints on theoretical models of new physics. The calculations are intended to be sufficiently precise that it is now necessary to include the effects of virtual photons. This project will include them.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.