NUMERICAL STUDY OF LATTICE QUANTUM CHROMODYNAMICS

晶格量子色动力学的数值研究

基本信息

批准号：
06640372
负责人：
UKAWA Akira
金额：
$ 1.15万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06640372/
关键词：
PARTCLE PHYSICS STRONG INTERACTIONS LATTICE QCD NUMERICAL SIMULATION WEAK INTERACTION CP VIOLATION CKM MATRIX B MESON 量子色力学格子ゲージ理論

项目摘要

Numerical simulations of lattice QCD provides a viable method for determination of the strong interaction corrections to weak amplitudes of hadrons, which is crucial for elucidating unsolved problems of weak interactions of elementary particles including the origin of CP violation. The objective of the present research is to carry out a systematic study of lattice QCD in this direction.In 1994 we applied the method of wall source without gauge fixing, previously developed by us, to the problem of pi-N sigma term and the quark content of proton spin. Both these matrix elements receive contributions from sea quark loops, and how one can evaluate these contributions represents a general problem that also appear in weak matrix element calculations. We found that the method works well, and that the values obtained are consistent with experiments, strongly indicating for the first time that QCD successfully explains the values of these observables long debated in particle theory.In the same … More year we also started preparations for Fujitsu VPP500/80 vector parallel supercomputer, which was scheduled to be installed at KEK in January 1995. A variety of lattice QCD codes were written, and tested intensively in the period January-March 1995.In April 1995 we have initiated large scale lattice QCD calculations of a variety of weak matrix elements of hadrons on VPP.The present status of the calculations are as follows.(1) The K Meson B parameter is one of the fundamental quantity for fixing the Cabibbo-Kobayashi-Maskawa quark mixing matrix. A quenched calculation of this quantity with the Kogut-Susskind quark action is well underway. So far data for 6 values of lattice spacings have been collected, and a calculation for one more value of lattice spacing is planned. Together the data should allow a precision extrapolation of the B parameter to the continuum limit. A similar calculation with the Wilson quark action, based on the method of chiral Ward identities developed this year, is also underway.(2) Another parameter important for CP violation studies is the B meson decay constant. An initial calculation made in the early summer of 1995 revealed large statistical fluctuations. A method of smeared source for reducing the error was tested, and a new calculation has been started late 1995. Data for two values of lattice spacing have been collected and a further calculations with reduced lattics spacing is planned to start soon. This will allow us to estimate the continue m value of the decay constant.(3) Tests of Clover quark action, expected to have a faster approach to the continuum limit, has been completed. Real calculations will start as soon as the Wilson calculation in (2) will be finished.We expect to be able to publish final results of these calculations by summer of 1996. Less

晶格QCD的数值模拟提供了一种可行的方法，用于确定强烈的相互作用校正对弱化的弱振幅，对于阐明弱相互作用的弱相互作用的弱点，包括违反CP的启发。 y yous，pi-n sigma项和质子旋转的夸克含量。在粒子理论中进行了长时间的讨论。在相同的... Fujitsu VPP500/80矢量平行超级计算机的artional中，该载体安排在1995年1月在Kek安装。编写了Lattice QCD代码，并在1月至1月的一月 - 一月 - 一月进行了经过深入测试。 1995年3月。在VPP上的多种弱矩阵元素的耕种。计算的存在如下（1）k meson b参数用于固定Cavayash-Maskawa Quark矩阵的固定。到目前为止，Kogut-Suspension Quark的动作正在进行中。 1995年，大量的统计学作品减少了误差，并计划了新的计算。预计将在（2）中的威尔逊计算后立即采取更快的方法。