Direct determinations of the nucleon and pion $\sigma$ terms at nearly physical quark masses
Direct determinations of the nucleon and pion $\sigma$ terms at nearly physical quark masses
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DOI：
10.1103/physrevd.93.094504
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发表时间：
2016-03
影响因子：
5
通讯作者：
G. Bali;S. Collins;Daniel Richtmann;A. Schafer;W. Soldner;A. Sternbeck
中科院分区：
文献类型：
--
作者：
G. Bali;S. Collins;Daniel Richtmann;A. Schafer;W. Soldner;A. Sternbeck
为260兆电子伏。人们发现，系统分类是合理可控的。对于核子，我们得到N = 35(6) MeV和s = 35(12) MeV，或者等效地用夸克分数表示，fTu = 0:021(4),fTd = 0:016(4)和fTs = 0:037(13)，其中误差包括对系统和统计不确定性的估计。这些值，加上重夸克极限中的微扰匹配，导致fTc = 0:075(4), fTb = 0:072(2)和fTt = 0:070(1)。此外，通过使用（逆）费曼-赫尔曼定理，我们的N的结果与分析中确定的核子质量一致。对于介子，我们实现了一种方法，该方法大大减少了穿越时间边界的状态对标量矩阵元素的激发态污染。这使我们能够证明在我们的介子质量范围内，Gell-Mann-Oakes-Renner期望值= m =2。
for m & 260 MeV. Systematics are found to be reasonably under control. For the nucleon we obtain N = 35(6) MeV and s = 35(12) MeV, or equivalently in terms of the quark fractions,fTu = 0:021(4),fTd = 0:016(4) and fTs = 0:037(13), where the errors include estimates of both the systematic and statistical uncertainties. These values, together with perturbative matching in the heavy quark limit, lead to fTc = 0:075(4), fTb = 0:072(2) and fTt = 0:070(1). In addition, through the use of the (inverse) Feynman-Hellmann theorem our results for N are shown to be consistent with the nucleon masses determined in the analysis. For the pion we implement a method which greatly reduces excited state contamination to the scalar matrix elements from states travelling across the temporal boundary. This enables us to demonstrate the Gell-Mann-Oakes-Renner expectation = m =2 over our range of pion masses.