Lattice QCD studies of the spectrum and structure of hadron excitations

强子激发的物理学，如N*共振，杂化介子和重子，其中价夸克被激发的胶子束缚？Eld，胶球，双粲重子，以及最近发现的五夸克系统，将通过计算机模拟时空晶格上的夸克和胶子进行研究。这样的系统应该能提供丰富的信息，帮助我们理解诈骗的物理原理。量子色动力学中的元素和强子的形成，强相互作用的理论和自然的基本力量之一。这些状态目前也引起了实验学家的极大兴趣，例如？由Hall B N*项目和在Thomas Je？美国国家加速器设施，以及康奈尔大学的CLEO-c项目。理解骗术的物理原理？宁胶子是一个重要的智力挑战；事实上，它是由马萨诸塞州剑桥克莱数学研究所宣布的所谓的七个千禧年奖问题之一。研究这类系统最可靠的方法之一是使用计算机模拟时空晶格上的夸克和胶子。直到最近，这些州都是零。因此，邪教模拟很少受到关注。格子模拟技术的进展(在各向异性格子上使用更好的规范和费米子作用，大相关矩阵变分技术的应用，约束曲线？（使用贝叶斯先验）和计算技术（集群，显著更快的处理器）不仅可以确定这些激发的光谱，还可以探测它们的内部结构。rst时间。卡内基梅隆大学、马里兰大学帕克分校、加州大学圣地亚哥分校和jj ？个人实验室将被用来进行这些模拟。本文的主要目的是利用蒙特卡罗方法计算光-夸克混合介子和重子、N*激发、双粲重子和五夸克态的质谱。另一个关键目标是研究一个静态夸克-反夸克对和三个静态夸克存在下胶子的稳态激发谱和结构。该提案还包括确定低洼的纯规胶球的空间大小和内部结构，以及测试各种con？利用胶球光谱进行分析。拟议的研究包括三名研究生的参与，可能还有一名或多名本科生，他们的教育将不仅通过参与科学研究而得到加强。C项目在核理论的前沿，同时也与高科技培训在最先进的并行计算资源的使用。拟议活动的更广泛影响将通过公布simpli？在可公开访问的网页上提供背景资料。

A Project summary The physics of hadron excitations, such as the N* resonances, hybrid mesons and baryons in which the valence quarks are bound by an excited gluon ?eld, glueballs, doubly-charmed baryons, and the recently-discovered pentaquark systems, will be studied using computer simulations of quarks and gluons on a space-time lattice. Such systems should provide a wealth of information to help us understand the physics of con?nement and hadron formation in quantum chromodynamics, the theory of the strong interactions and one of the fundamental forces of Nature. These states are also currently of great interest to experimentalists, exempli?ed by the Hall B N* program and the GlueX experiment in the proposed Hall D at the Thomas Je?erson National Accelerator Facility, as well as the CLEO-c project at Cornell. Understanding the physics of con?ning 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 computer simulations of quarks and gluons on a space-time lattice. Until recently, these states were di?cult to simulate and hence, received little attention. Advances in lattice simulation technology (the use of better gauge and fermion actions on anisotropic lattices, the application of variational techniques with large correlation matrices, constrained curve ?tting using Bayesian priors) and computing technology (clusters, dramatically faster processors) make it possible not only to determine the spectra of such excitations, but also to probe their internal structures for the ?rst time. Commodity computing clusters at Carnegie Mellon University, the University of Maryland at College Park, the University of California at San Diego, and Je?erson Laboratory will be used to carry out these simulations. A major objective of this proposal is to calculate the mass spectrum of light-quark hybrid mesons and baryons, the N* excitations, doubly-charmed baryons, and pentaquark states using Monte Carlo methods with large sets of well-designed operators. Another key goal is to study the excitation spectrum and structures of the stationary states of gluons in the presence of a static quark-antiquark pair and three static quarks. The proposal also includes plans to determine the spatial sizes and internal structures of the low-lying pure-gauge glueballs, and to test various models of con?nement using the glueball spectrum. The proposed research incorporates the participation of three graduate students, and possibly one or more undergraduate students, whose educations will be enhanced not only by involvement in scienti?c 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 simpli?ed background information on publicly accessible web pages.