Influence of dynamical strange quark on finite-temperature QCD transition

动力奇夸克对有限温度QCD跃迁的影响

• 批准号: 13640260
• 负责人: KANAYA Kazuyuki
• 金额: $ 2.37万
• 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 (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13640260/
• 关键词: Particle Physics; Quark Gluon Plasma; Finite Temperature; Strange Quark; Lattice Gauge Theory; Anisotropic Lattice; Numerical Simulations; Lattice QCD; 格子場の理論

Through a series of evidences, the quark-gluon plasma seems to be created in the early stage of relativistic heavy-ion collisions at RHIC. In order to extract thermodynamic properties of the quark-gluon plasma quantitatively, a lattice calculation of finite temperature QCD-directly from the first principles of QCD-is indispensable. Because the typical energy scale given by the QCD transition temperature is about the strange quark mass, a realistic simulation require a dynamical treatment of the strange quark (three-flavor QCD) besides conventional up and down quarks (two-flavor QCD). Due to various difficulties, however, most large-scale simulations have been done in two-flavor QCD.Toward a realistic simulation of the quark-gluon plasma, this project aims at a systematic study of three-flavor QCD. We also study efficient methods for thermodynamic quantities in finite-temperature lattice QCD.As the first step of the three-flavor project, we carried out a systematic comparison of various … More exact algorithms proposed recently for QCD with odd number of flavors. We found a version of the PHMC algorithm is efficient enough for a systematic study of three-flavor QCD. From a preparative simulation using the PHMC algorithm, we also find that improvement of both gauge and quark actions is indispensable for a continuum extrapolation with present power of computers. Finally we determined non-perturbative values of the improvement parameter c_<sw> at relevant coupling parameters.Based on these results, we started a systematic study of hadronic spectroscopy in three-flavor QCD at zero temperature. We studied at three lattice spacings, 0.122, 0.10, and 0.07 fm, on 16^3x32, 20^3x40, and 24^3x56 lattices, respectively. Simulations on the first two lattices have been completed, and that on the finest lattice on-going. We confirmed that, in contrast to the discrepancy of quenched spectrum observed in a previous study, three-flavor QCD reproduces experimental meson spectrum correctly. We also found that the light u,d quark mass and the s quark mass are about 20--30% smaller than those evaluated previously in the quenched QCD.We also studied efficient methods to calculate the equation of state and thermodynamic quantities in finite-temperature QCD. In a quenched simulation, we have shown that anisotropic lattices provide us with such an efficient way. Accordingly, we have carried out the first controlled continuum extrapolation of the equation of state using data at three lattice spacings. To carry out a more realistic calculation in QCD with dynamical quarks, we evaluated non-perturvative values of anisotropy coefficients in two-flavor QCD with improved quark and gluon actions. Less

通过一系列证据，夸克-胶子等离子体似乎是在RHIC相对论性重离子碰撞的早期阶段产生的。为了定量提取夸克-胶子等离子体的热力学性质，进行了有限温度QCD-的晶格计算。直接来自 QCD 的第一原理是必不可少的，因为 QCD 转变温度给出的典型能量尺度与奇异夸克质量有关，所以现实的模拟需要对奇夸克质量进行动态处理。然而，由于各种困难，大多数大规模模拟都是在二味 QCD 中完成的。胶子等离子体，该项目旨在系统研究三味QCD，我们还研究有限温度晶格QCD中热力学量的有效方法。作为三味项目的第一步，我们。对最近提出的具有奇数口味的 QCD 的各种算法进行了系统比较，我们发现 PHMC 算法的一个版本对于使用 PHMC 算法的预备模拟来说对于三口味 QCD 的系统研究来说足够有效。 ，我们还发现规范和夸克作用的改进对于现有计算机能力的连续外推是必不可少的，最后我们确定了相关耦合处改进参数 c_<sw> 的非微扰值。基于这些结果，我们开始了零温度下三味 QCD 强子光谱的系统研究。我们在 16^3x32、20^3x40 和 24 上以 0.122、0.10 和 0.07 fm 三种晶格间距进行研究。 ^3x56 格子，前两个格子的模拟已经完成，并且我们证实，与之前研究中观察到的淬灭光谱的差异相比，三味 QCD 正确地再现了实验介子光谱。夸克质量比之前在淬火QCD中评估的质量小约20--30%。我们还研究了计算有限温度QCD中的状态方程和热力学量的有效方法。通过淬火模拟，我们已经证明各向异性晶格为我们提供了这种有效的方法，因此，我们使用三个晶格间距的数据进行了状态方程的首次受控连续外推，以在 QCD 中进行更真实的计算。利用动态夸克，我们评估了具有改进的夸克和胶子作用的双味 QCD 中各向异性系数的非扰动值。

项目成果

Light hadron spectroscopy in two-flavor QCD with small sea quark masses

小海夸克质量的双味 QCD 中的光强子光谱

• 发表时间: 2004
• 期刊: Phys. Rev. D 70
• 作者: K.Sadakane;T.Ohnishi;M.Ohkubo;Y.Takeda;Y.Takeda et al.;E.Shintani et al.;Tatsuyuki Takatsuka;S.Aoki;K.Sadakane et al.;Tatsuyuki Takatsuka;Y.Namekawa
• 通讯作者: Y.Namekawa

Light hadron spectrum in 2+1 flavor full QCD by CP-PACS and JLQCD Collaborations

CP-PACS 和 JLQCD 合作的 2 1 风味全 QCD 中的轻强子谱

• 发表时间: 2005
• 期刊: Nucl. Phys. B 140(Proc. Suppl.)
• 作者: Yasutake;N.;S.Aoki;T.Ishikawa et al.;T.Ishikawa
• 通讯作者: T.Ishikawa

S.Aoki et al.: "Non-Perturbative Determination of C_<sw> in Three-flavor Dynamical QCD"Nucl.Phys.B(Proc.Suppl.). 119. 433-435 (2003)

S.Aoki 等人：“三味动态 QCD 中 C_<sw> 的非微扰测定”Nucl.Phys.B（Proc.Suppl.）。

Recent lattice results relevant for heavy ion collisions

最近与重离子碰撞相关的晶格结果

• 发表时间: 2003
• 期刊: Nucl.Phys. A715
• 作者: CP-PACS Collaboration : Y.Namekawa;S.Aoki;M.Fukugita;K-I.Ishikawa;N.Ishizuka;Y.Iwasaki;K.Kanaya;T.Kaneko;Y.Kuramashi;V.I.Lesk;M.Okawa;A.Ukawa;T.Umeda;T.Yoshie;T.Onogi et al.;N.Tsutsui et al.;K-I.Ishikawa et al.;T.Yamazaki et al.;K.Ide et al.;S.Aoki et al.;S.Aoki et al.;S.Aoki et al.;T.Yamazaki et al.;K.Ide et al.;S.Takeda et al.;CP-PACS et al.;S.Aoki et al.;Kazuyuki Kanaya
• 通讯作者: Kazuyuki Kanaya

Scaling study of the step scaling function in SU(3) gauge theory with improved gauge actions

SU(3)规范理论中改进规范作用的阶跃标度函数的标度研究

• 发表时间: 2004
• 期刊: Physiol review D 70
• 作者: Fujita H.;et al.;Shinji Takeda(CP-PACS)
• 通讯作者: Shinji Takeda(CP-PACS)