Nucleon sigma term and strange quark content from lattice QCD with exact chiral symmetry
Nucleon sigma term and strange quark content from lattice QCD with exact chiral symmetry
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DOI：
10.1103/physrevd.78.054502
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发表时间：
2008-06
影响因子：
5
通讯作者：
H. Ohki;H. Ohki;H. Fukaya;S. Hashimoto;S. Hashimoto;T. Kaneko;T. Kaneko;H. Matsufuru;J. Noaki-J.
中科院分区：
文献类型：
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作者：
H. Ohki;H. Ohki;H. Fukaya;S. Hashimoto;S. Hashimoto;T. Kaneko;T. Kaneko;H. Matsufuru;J. Noaki-J.
我们利用费曼 - 海尔曼定理在两味晶格量子色动力学中计算核子西格玛项。海夸克和价夸克均由重叠费米子公式描述，该公式在晶格上保留了精确的手征和味对称性。我们使用从重子手征微扰理论导出的解析公式来分析核子质量的晶格数据。从价夸克质量设定不同于海夸克质量的数据中，我们可以提取出海夸克对西格玛项的贡献，这对应于奇夸克成分。我们发现奇夸克成分比之前的晶格计算和唯象估计要小得多。
We calculate the nucleon sigma term in two-flavor lattice QCD utilizing the Feynman-Hellman theorem. Both sea and valence quarks are described by the overlap fermion formulation, which preserves exact chiral and flavor symmetries on the lattice. We analyze the lattice data for the nucleon mass using the analytical formulae derived from the baryon chiral perturbation theory. From the data at valence quark mass set different from sea quark mass, we may extract the sea quark contribution to the sigma term, which corresponds to the strange quark content. We find that the strange quark content is much smaller than the previous lattice calculations and phenomenological estimates.