Nonperturbative tuning of an improved relativistic heavy-quark action with application to bottom spectroscopy
Nonperturbative tuning of an improved relativistic heavy-quark action with application to bottom spectroscopy
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DOI：
10.1103/physrevd.86.116003
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发表时间：
2012-06
影响因子：
5
通讯作者：
Y. Aoki;N. Christ;J. Flynn;T. Izubuchi;C. Lehner;Min Li;Hao Peng;A. Soni;R. V. D. Water;O. Witzel
中科院分区：
文献类型：
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作者：
Y. Aoki;N. Christ;J. Flynn;T. Izubuchi;C. Lehner;Min Li;Hao Peng;A. Soni;R. V. D. Water;O. Witzel
我们用改进的相对论作用量和RBC/UKQCD岩崎规范位形计算了底介子的质量。我们分析了具有两个晶格间距的组态：a^{-1} = 1.729 GeV（a ~ 0.11 fm）和a^{-1} = 2.281 GeV（a ~ 0.086 fm）。我们对b夸克采用各向异性的、三叶草改进的Wilson作用量，并非微扰地调节作用量的三个参数，使它们重现B_s和B_s* 重-轻介子态的实验值。在不需要额外输入的情况下，计算出了低位bottomonium态（如eta_B和Upperdum）的质量和质量分裂，并将计算结果与实验结果进行了比较，验证了方法的有效性.我们得到的bottomonium质量与总的不确定性为~0.5-0.6%和精细结构分裂的不确定性为~35-45%，在所有情况下，我们发现与实验吻合得很好。在这项工作中提出的相对论重夸克作用量的参数调整为b夸克，可以用于精确计算弱矩阵元素，如B介子衰变常数和混合参数的晶格离散化误差是相同的大小，在轻赝标介子量。如果重夸克作用量的参数被适当地调整，这个一般方法也可以用于粲介子质量和矩阵元。
We calculate the masses of bottom mesons using an improved relativistic action for the b-quarks and the RBC/UKQCD Iwasaki gauge configurations with 2+1 flavors of dynamical domain-wall light quarks. We analyze configurations with two lattice spacings: a^{-1} = 1.729 GeV (a ~ 0.11 fm) and a^{-1} = 2.281 GeV (a ~ 0.086 fm). We use an anisotropic, clover-improved Wilson action for the b-quark, and tune the three parameters of the action nonperturbatively such that they reproduce the experimental values of the B_s and B_s* heavy-light meson states. The masses and mass-splittings of the low-lying bottomonium states (such as the eta_b and Upsilon) can then be computed with no additional inputs, and comparison between these predictions and experiment provides a test of the validity of our method. We obtain bottomonium masses with total uncertainties of ~0.5-0.6% and fine-structure splittings with uncertainties of ~35-45%; for all cases we find good agreement with experiment. The parameters of the relativistic heavy-quark action tuned for b-quarks presented in this work can be used for precise calculations of weak matrix elements such as B-meson decay constants and mixing parameters with lattice discretization errors that are of the same size as in light pseudoscalar meson quantities. This general method can also be used for charmed meson masses and matrix elements if the parameters of the heavy-quark action are appropriately tuned.