Novel Development of Research of 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研究格子标准模型的新进展

基本信息

批准号：
12304011
负责人：
IWASAKI Yoichi
金额：
$ 28.1万
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：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12304011/
关键词：
STANDARD MODEL LATTICE QCD NUMERICAL SIMULATION CP VIOLATION B PARAMETER B MESON DOMAIN WALL FERMION CHARMONIUM 数値シュミレーションクォークグルオンプラズマ

项目摘要

This work aimed to elucidate the nature of strong interactions based on lattice QCD using the massively parallel computer CP-PACS developed at University of Tsukuba. The main results achieved over the three year period of the present Grant-in-aid are as follows :1. Calculation of weak matrix elements using the domain wall fermion formalism.Taking advantage of the good chiral property of the domain wall fermion action, the kaon B parameter was evaluated using RG-improved gauge action at 1/a=2 GeV and 3GeV. The results showed only small scaling violations, and using perturbative renormalization factor, we obtained B_k(2G_eV)=0.5746(61)(191), to be compared with the previous best estimate using the KS formalism : B_k(2G_eV)=0.628(41).Another problem addressed is K→π π decay amplitudes. Using chiral perturbation theory formuli which relates K→π π to K→π amplitudes, we found the following : I) The real part of the I=2 amplitude is consistent with experiment, while that of the I=0 amplitude … More is only about half of the physical one. Thus theΔI=0 = 1/2 enhancement is only half of experiment. Ii) The imaginary Part exhibits a similar feature that the I=0 amplitude is too small ; consequently the direct CP violation parameter e'/e=-1x10^<-4> is negative and too small. The origin of these unsatisfactory results needs to be clarified.2. Lattice QCD on anisotropic latticesSpace-time anisotropic lattices are useful in a variety of contexts including calculations of heavy quark hadrons and finite-temperature QCD. Charmonium spectroscopy and equation of state studies were made using quenched anisotropic lattices. To advance the use of anisotropic lattices in full QCD, first attempt to determine the anisotropy parameters of the action was made for two flavor full QCD.3. Small quark mass and chiral behaviorChiral estrapolation is the most uncertain of the extrapolations in today's lattice QCD calculations. Simulations reducing the quark mass as small as m_n/m_p=0.4 were attempted at a coarse lattice spacing of 1/a=1GeV. Compared to simulations down to m_n/m_p=0.6, physical predictions in the chiral limit differ by about 10%. The HMC algorithm also develop an instability whose origin was investigated.4. Preparations toward Nf=2+1 full QCD simulationsTruly realistic simulations of QCD requires including dynamical effects of strange quark. We showed that the polynomial HMC algorithm is suitable for this purpose. To carry out a fully O(a) improved simulation for Nf=2+1 using the RG-improved action, the clover coefficient for Nf=3 theory was determined. The results will be used to carry out Nf=2+1 full QCD simulations which incorporates dynamical sea quark effects of up, down and strange quark. Less

这项工作旨在使用大量计算机CP-PAC在tsukuba上阐明晶格QCD的TRE。使用域壁形式主义的弱矩阵。使用rg改进的仪表作用在1/a = 2 GEV和3GEV的情况下评估了域壁作用的良好手性特性。并使用KS形式主义使用先前的最佳估计值使用扰动重新归一化因子：b_k（2g_ev）= 0.628（41）。其他问题添加的问题是k→πππππππππππ</s> </s> </s> </s> </s s> </s > </s> </s> </s>ππππππππ→π→πound以下：i）i = 2振幅的实际部分与经验一致，而i = 0的实际部分是i = 0的幅度，大约是一半实验的唯一一半都表现出类似的特征澄清。 QCD.3。算法还会发展出一个不稳定性。4。 a）使用RG改进的动作改进了NF = 2+1的仿真，NF = 3的三叶草共同点将进行NF = 2+1完整的QCD模拟ICH ICH ICH结合了向上，下和奇怪的动态海夸克效应夸克。