Development of Research on the Standard Model on the Lattice using the Massively Parallel Computer CP-PACS

利用大规模并行计算机CP-PACS进行格子标准模型研究进展

• 批准号: 09304029
• 负责人: IWASAKI Yoichi
• 金额: $ 20.8万
• 依托单位: University of Tsukuba
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09304029/
• 关键词: numerical simulation; parallel computer; CP-PACS; lattice QCD; hadron; quenched approximation; full QCD; improved lattice action; 数値シュミレーション; 改良された作用; 有限温度QCD; 相転移; フレーバー; numerical simulation; parallel computer; CP-PACS; lattice QCD; hadron; quenched approximation; full QCD; improved lattice action; 数値シュミレーション; 改良された作用; 有限温度QCD; 相転移; フレーバー

This research program aimed to exploit the high computational power of the CP-PACS computer for significantly advancing the study of the non-perturbative aspects of the Standard Model using the lattice formulation of QCD. Specifically, we concentrated on the following subjects :(i) To obtain precise light hadron spectrum in quenced lattice QCD, we carried out an extensive simulation with the standard plaquette gauge action and the Wilson quark action employing large lattices and high statistics. For the first time, we clearly showed that the quenched light hadron spectrum deviates from the experiment by about 10% due to the quenched approximation.(ii) From a systematic study of full GCD with two flavors of light dynamical quarks using an improved action, we showed that the hadron spectrum becomes much closer to experiment than the quenched approximation. The values for light quark masses from full QCD are 20-30% smaller than those in the quenched QCD. The decay constant for B and Bs me … More sons, which are important in a study of the weak interaction, is larger by about 10% in full QCD. The η' meson mass in the continuum limit is close to the experiment, suggesting that the U(1) problem is solved in QCD.(iii) We studied the finite-temperature phase transition and equation of state of QCD using the same improved action as employed in (ii). For the pure gluon theory, we found that the equation of state in the continuum limit agrees well with that obtained with the standard action, demonstrating high reliability of our methods. This work has been extended to full QCD with two flavors of quarks. The phase structure was explored and the equation of state was calculated on an NィイD2tィエD2 = 4 lattice.(iv) Domain-wall QCD offers a possibility to resolve the problem of broken chiral symmetry in the conventional formulations of lattice quarks. As a first step to establish its viability, we studied chiral properties as a function of various parameters of the formalism. We found that exact chiral symmetry is realized for sufficiently fine lattices, while the formalism does not work on coarse lattices. Here, an improved gauge action shows improved chiral symmetry. Work is now extended to calculations of physical matrix elements relevant for CP violation studies. Less

该研究计划旨在探索CP-PACS计算机的高计算能力，以便使用QCD的晶​​格公式对标准模型的非扰动方面进行显着推进。具体而言，我们专注于以下主题：（i）为了获得效率的晶格QCD中的精确轻型黑岩光谱，我们对标准的Plaquette Gauge Action进行了广泛的模拟，并采用大型晶格和高统计数据进行了Wilson Quark Action。我们首次清楚地表明，由于猝灭的近似值，淬灭的光线频谱偏离了实验的偏差约10％。（ii）通过使用改进的动作进行了两种轻型动态夸克的系统研究，我们显示了强体光谱比淬灭的近似更接近实验。来自全QCD的光夸克质量的值比QCD中的QCD小20-30％。 B和BS ME的衰减常数……在对弱相互作用的研究中，更多的儿子在完整的QCD中较大约10％。连续限量中的η'Meson质量接近实验，这表明在QCD中解决了U（1）问题。（iii）我们研究了使用（II）中携带的相同改进的动作来研究有限温度的相变和QCD状态的方程。对于纯粹的gluon理论，我们发现持续极限中的状态方程与标准作用相符的状态非常吻合，这表明我们方法的可靠性很高。这项工作已扩展到完整的QCD，并带有两种夸克风味。探索了相结构，并在nyi d2tie d2 = 4晶格上计算状态方程。（iv）域壁wall qCD提供了解决晶状体夸克常规公式中损坏手性对称性问题的可能性。作为建立生存能力的第一步，我们研究了手性特性，这是形式的各种参数的函数。我们发现，确切的手性对称性是为了足够细的晶格而实现的，而形式不适用于粗晶格。在这里，改进的仪表作用显示了改善的手性对称性。现在，工作扩展到与CP违规研究相关的物理矩阵元素的计算。较少的