Strangeness contribution to the proton spin from lattice QCD.
Strangeness contribution to the proton spin from lattice QCD.
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DOI：
10.1103/physrevlett.108.222001
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发表时间：
2011-12
影响因子：
8.6
通讯作者：
G. Bali;S. Collins;M. Göckeler;R. Horsley;Y. Nakamura;A. Nobile;D. Pleiter;P. Rakow;A. Schäfer;G. Schierholz;J. Zanotti
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文献类型：
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作者：
G. Bali;S. Collins;M. Göckeler;R. Horsley;Y. Nakamura;A. Nobile;D. Pleiter;P. Rakow;A. Schäfer;G. Schierholz;J. Zanotti
我们用非微扰改进的Sheikholeslami-Wohlert Wilson作用量计算了n（f）=2格点QCD中π质量约为285 MeV，格点间距a = 0.073 fm时奇异度和轻夸克对质子自旋的贡献Δs，Δu和Δd.我们进行这些矩阵元素的重整化，这涉及到不同夸克口味的贡献之间的混合。我们的主要结果是奇异度对核子自旋的贡献有一个小的负值Δs（MS）=-0.020（10）（4）.第二个误差是对不确定性的估计，这是由于缺少对物理点的外推。
We compute the strangeness and light-quark contributions Δs, Δu, and Δd to the proton spin in n(f)=2 lattice QCD at a pion mass of about 285 MeV and at a lattice spacing a≈0.073 fm, using the nonperturbatively improved Sheikholeslami-Wohlert Wilson action. We carry out the renormalization of these matrix elements, which involves mixing between contributions from different quark flavors. Our main result is the small negative value Δs(MS)(√(7.4) GeV)=-0.020(10)(4) of the strangeness contribution to the nucleon spin. The second error is an estimate of the uncertainty, due to the missing extrapolation to the physical point.