Lattice Field Theory and Hadronic Physics

相当大的理论进步和计算机技术的巨大进步使晶格成为可能。场理论是研究核和亚核结构的有力工具。所提议的活动具有以下智力优点：i)提出新的想法和探索新的理论方法来计算有趣的新物理量；Ii)利用现有的技术以及最先进的计算机来获得实验感兴趣的结果。晶格QCD的计算通常是在淬火近似下进行的。猝灭效应将用具有精确手性对称的晶格费米子进行详细研究。超出淬火近似的计算是计算密集型的，平面QCD将被研究，看看它是否是物理上可行的替代方案。外来杂化介子含有价胶子，只能在量子光盘的框架下进行适当的研究。计划在JLab D厅进行的实验计划寻找这种奇异的混合介子。计算它们的衰变宽度将为这些奇异杂化体的实验搜索提供一些指导。点阵QCD将用于研究双强子系统中的核力。它还将用于研究强子的电和磁极化率。这些计算在技术上是复杂的，结果将大大增加我们对核相互作用的理解。rst原则。QCD中的手性对称性在低温下会自发破坏，但在高温下有望恢复。夸克-胶子等离子体描述的高温QCD。利用带手性费米子的晶格QCD研究手性相变的物理性质。瞬时子的作用。夜间温度将被仔细研究。所提出的研究将大有裨益。由一名全职博士后和一名研究生参与。与pi密切合作的研究生和博士后将熟悉核理论前沿的研究，并在使用最先进的并行计算资源方面得到良好的培训。作为拓展计划的一部分，一名高年级物理系学生将被雇用建立一个网站，以高中生、教师和当地社区为对象介绍这些项目。通过专注于高专业。目前，国家实验室对这一课题非常感兴趣，该提案希望能帮助当地大学努力吸引来自未被充分代表群体的新生。

Considerable theoretical progress combined with enormous advances in computertechnology has made lattice .eld theory a powerful tool in the study ofnuclear and sub-nuclear structure. The proposed activity has the following intellectualmerits: i) proposal of new ideas and exploration of new theoreticalapproaches to compute interesting novel physical quantities; ii) use of existingtechniques along with state-of-the-art computers to obtain results of experimentalinterest.Calculations in lattice QCD are often performed in the quenched approximation.Quenching e.ects will be studied in detail using lattice fermions thathave exact chiral symmetry. Calculations beyond the quenched approximationare computationally intensive and planar QCD will be studied to see if it is aphysically viable alternative.Exotic hybrid mesons contain valence gluons and can only be studied properlyin the framework of QCD. Experiments scheduled in Hall D at JLab planto look for such exotic hybrid mesons. Computations of their decay widths willbe performed to provide some guidance for the experimental searches of theseexotic hybrids.Lattice QCD will be used to study nuclear forces present in a two hadronsystem. It will also be used to study the electric and magnetic polarizabilities ofhadrons. These computations are technically involved and results would considerablyincrease our understanding of nuclear interactions from .rst principles.Chiral symmetry in QCD is spontaneously broken at low temperatures butit is expected to get restored at high temperatures. QCD at high temperaturesis described by a quark-gluon plasma. The physics around the chiral phasetransition will be investigated using lattice QCD with chiral fermions. The roleof instantons at .nite temperature will be carefully studied.The proposed research will greatly bene.t from the participation of a fulltimepostdoctoral fellow and a graduate student. The graduate student workingin close association with the PIs and the postdoctoral fellow will become familiarwith the research done at the forefront of nuclear theory and also get a goodtraining in the use of state-of-the-art parallel computing resources. As part ofthe outreach program, a senior physics student will be employed to set up awebsite describing the projects at a level that is accessible to high school students,teachers and the local community at large. By focusing on high pro.letopics currently of great interest at national laboratories, the proposal hopes toassist in the e.orts of the local university to attract new students from underrepresentedgroups.