Lattice QCD studies of the spectrum and structure of hadron excitations

强子激发的物理学，例如N* 共振，混合介子和重子，其中价夸克被激发的胶子束缚？场，胶球，双魅重子，和最近发现的五夸克系统，将使用计算机模拟的夸克和胶子的时空晶格进行研究。这样的系统应该提供了丰富的信息，以帮助我们理解的物理con？在量子色动力学中，强相互作用的理论和自然界的基本力量之一。这些国家目前也很感兴趣的实验，exempli？艾德的霍尔B N* 计划和GREX实验在拟议的D大厅在托马斯杰？美国国家加速器设施，以及康奈尔大学的CLEO-c项目。明白骗局的原理吗？研究胶子是一项重要的智力挑战;事实上，它是马萨诸塞州剑桥的克莱数学研究所宣布的七个所谓的千禧年奖问题之一。研究这类系统最可靠的方法之一是利用计算机模拟时空晶格上的夸克和胶子。直到最近，这些国家都是迪？因此，很少有人注意到。晶格模拟技术的进展（在各向异性晶格上使用更好的规范和费米子作用，应用变分技术与大的相关矩阵，约束曲线？设置使用贝叶斯先验）和计算技术（集群，显着更快的处理器），使它不仅可以确定这种激励的频谱，但也探测其内部结构的？第一次。卡内基梅隆大学、马里兰州大学帕克分校、加州大学圣地亚哥分校和Je？埃尔森实验室将被用来进行这些模拟。这个提议的一个主要目标是使用蒙特卡罗方法和大量精心设计的算子来计算轻夸克混合介子和重子，N* 激发，双粲重子和五夸克态的质量谱。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时胶子定态的激发谱和结构。该提案还包括计划，以确定空间大小和内部结构的低洼纯规格胶球，并测试各种型号的康？nement使用glueball胶球spectrum光谱.拟议的研究纳入了三个研究生的参与，可能还有一个或多个本科生，他们的教育将得到加强，不仅参与科学？c项目的前沿核理论，同时也具有高科技训练，使用最先进的并行计算资源。通过使用simpli？艾德在可公开访问的网页上提供背景信息。

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.