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arXiv 1104.4101hep-lat
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用各向异性三叶草晶格进行高统计分析:(IV)轻强子质量的体积依赖性

High Statistics Analysis using Anisotropic Clover Lattices: (IV) Volume Dependence of Light Hadron Masses

S. R. Beane, E. Chang, W. Detmold, H. W. Lin, T. C. Luu, K. Orginos, A. Parreno, M. J. Savage, A. Torok, A. Walker-Loud

摘要:

用格点量子色动力学研究了八重态重子质量的体积依赖性及其相互关系。计算采用nf =2+1的Clover费米子离散在四个格点体积中,空间范围L ~ 2.0,2.5,3.0和3.9fm,各向异性格点间距在空间方向上为bs ~ 0.123fm,在时间方向上为bt = bs/3.5,π质量为mpi ~ 390 MeV。基态重子质量测定的典型精确度为~ 0.2%,使得能够精确探索质量的体积依赖性、盖尔曼-大久保质量关系以及其他质量组合。在SU(2)_LXSU(2)_R和SU(3)_LXSU(3)_R展开下,将体积依赖性与重子手征微扰理论的预言进行了比较.强子质量的三味膨胀的预测被发现合理地描述所观察到的体积依赖性。此外,Delta-N-pi轴向耦合常数是从两味展开中核子质量的体积依赖性中提取的,在三味展开中仅从包含K介子和等离子体中进行了小的修改。在给定的m_pi L值下,由于一个标度为~ m_pi ^[3]的系数,有限体积对核子质量的贡献在m_pi ~ 140 MeV时比在m_pi ~ 390 MeV时要小得多。这是相关的设计未来的系综格规范场配置。最后,用二味和三味手征微扰理论分析了π介子和K介子质量与体积的关系。

英文摘要:

The volume dependence of the octet baryon masses and relations among them are explored with Lattice QCD. Calculations are performed with n_f=2+1 clover fermion discretization in four lattice volumes, with spatial extent L ~ 2.0, 2.5, 3.0 and 3.9 fm, with an anisotropic lattice spacing of b_s ~ 0.123 fm in the spatial direction, and b_t = b_s/3.5 in the time direction, and at a pion mass of m_pi ~ 390 MeV. The typical precision of the ground-state baryon mass determination is ~0.2%, enabling a precise exploration of the volume dependence of the masses, the Gell-Mann--Okubo mass relation, and of other mass combinations. A comparison of the volume dependence with the predictions of heavy baryon chiral perturbation theory is performed in both the SU(2)_L X SU(2)_R and SU(3)_L X SU(3)_R expansions. Predictions of the three-flavor expansion for the hadron masses are found to describe the observed volume dependences reasonably well. Further, the Delta-N-pi axial coupling constant is extracted from the volume dependence of the nucleon mass in the two-flavor expansion, with only small modifications in the three-flavor expansion from the inclusion of kaons and etas. At a given value of m_pi L, the finite-volume contributions to the nucleon mass are predicted to be significantly smaller at m_pi ~ 140 MeV than at m_pi ~ 390 MeV due to a coefficient that scales as ~ m_pi^3. This is relevant for the design of future ensembles of lattice gauge-field configurations. Finally, the volume dependence of the pion and kaon masses are analyzed with two-flavor and three-flavor chiral perturbation theory.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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