Hadron Physics from Covariant QCD Modeling

项目摘要本提案要求三年的支持，以继续一项研究计划，涉及一名高级研究员，一名博士后研究员和几名学生。本研究将把对胶子、鬼子和夸克场的传播子和顶点的理解与介子协变模型的进展结合起来，从量子色动力学（QCD）的夸克和胶子的角度来研究强子和强子过程。主要研究者在强子的连续非微扰QCD模型和随后的强子过程的描述的基础上，Dyson-Schwinge方程的理论。以前的工作主要集中在解Dyson-Schwinger方程的穿着夸克传播子其次是解束缚态Bethe-Salpeter方程的介子。当微扰域用两个参数描述时，出现的有效相互作用近似于QCD的微扰短程行为。它产生了经验量的动力学手征对称性破缺，实现了与之密切相关的绝对夸克偶联现象。对于轻夸克的基态赝标和矢量介子以及重子，这种方法的明显成功需要与其他人最近的进展相协调，这些进展增加了我们对QCD规范玻色子扇区的理解。特别是，我们试图用QCD更基本的规范玻色子扇区的独立研究结果来代替上述有效相互作用的两个参数。至少对于我们希望连接到的胶子和鬼装扮传播子，有可用的规范扇区戴森-施温格方程的模型解。对于这些量和重要的胶子夸克顶点，也有来自QCD晶格模拟的独立质量数据。因此，发展由QCD数据约束的强子过程的连续模型的时机已经成熟。这些问题涉及夸克偶联的起源和动力学手征对称破缺。关于如何超越阶梯近似的信息是athand，将被使用。其结果将根据强子可观测量进行评估。这些信息对于我们进一步理解强子物理和了解QCD规范扇区的物理相关的非微扰动力学都是必要的。我们的结合方法将是对强子物理下占主导地位的夸克-胶子机制的连续庞加莱不变量研究的一个进步。该项目中的几项活动具有更广泛的影响。这项资助的研究有助于推动核物理和粒子物理的发展。强子性质和过程的夸克-胶子基础是核物理的一个重点领域，理论进展有助于JLab和RHIC实验设施的投资回报。这项工作也有助于通过培养研究生和博士后学者，并通过研究生和博士后学者参与本科教学的研究和教育的整合。学生也有机会参加专业会议。与德国图宾根大学的科学家进行的国际合作，需要执行该项目的一部分，有助于国家的研究和教育基础设施。

Project SummaryThis proposal requests three yeas of support to continue a research program involving one seniorinvestigator, one postdoctoral fellow and several students. The research will address hadronsand hadronic processes in terms of the con.ned quarks and gluons of Quantum Chromodynamics(QCD)b y joining recent advances in understanding the propagators and vertices involvinggluon, ghost and quark .elds with advances in covariant modeling of mesons, form factors andinteractions.The principal investigator has expertise in continuum nonperturbative QCD modeling ofhadrons and the subsequent description of hadronic processes based on the Dyson-Schwingerequations of the theory. Previous work has concentrated upon the solution of the Dyson-Schwinger equation for the dressed quark propagator followed by the solution of the boundstate Bethe-Salpeter equation for mesons. The e.ective interaction that has emerged preservesthe perturbative short distance behavior of QCD while the perturbative domain is describedwith two parameters. It generates the empirical amount of dynamical chiral symmetry breakingand the closely related phenomena of absolute quark con.nement is implemented. The evidentsuccess of this approach for the ground state pseudoscalar and vector mesons of light quarks,and for baryons, needs to be reconciled with recent advances by others that have increased ourunderstanding of the gauge boson sector of QCD.In particular, we seek to replace the two parameters of the above-mentioned e.ective interactionby results of independent studies of the more fundamental gauge boson sector of QCD. Thereare available model solutions of the gauge sector Dyson-Schwinger equations for at least the gluonand ghost dressed propagators that we wish to connect to. Also there is available independentquality data from lattice simulations of QCD for these quantities and for the important gluonquarkvertex. Thus the time is ripe for development of continuum models of hadronic processesconstrained by QCD data. These issues relate to the origin of quark con.nement and dynamicalchiral symmetry breaking. Information on how to move beyond the ladder approximation is athand and will be used. The consequences will be subjected to an evaluation in terms of hadronicobservables. This information is needed to both advance our understanding of hadron physicsand learn about the physically relevant nonperturbative dynamics of the gauge sector of QCD.Our combined approach will be an advance in continuum Poincare invariant investigations of thedominant quark-gluon mechanisms underlying hadron physics.Several activities within this project have broader impact. The research undertaken withthis grant helps to advance both nuclear and particle physics. The quark-gluon basis of hadronicproperties and processes is a focus area of nuclear physics and theoretical progress contributesto the return on the investment in the experimental facilities at JLab and RHIC. This work alsocontributes to the integration of research and education through the training of graduate studentsand postdoctoral scholars, and through the involvement of graduate students and postdoctoralscholars in undergraduate teaching. Also students get the opportunity to participate in professionalmeetings. The international collaborations with scientists at the University of Tuebingen,Germany, needed to carry out parts of this project contribute to the nation's infrastructure forresearch and education.