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arXiv 0907.4194hep-lat
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利用精细格点2+1味畴壁费米子和手征微扰理论计算格点量子色动力学中核子电磁形状因子

Nucleon Electromagnetic Form Factors from Lattice QCD using 2+1 Flavor Domain Wall Fermions on Fine Lattices and Chiral Perturbation Theory

S. N. Syritsyn, J. D. Bratt, M. F. Lin, H. B. Meyer, J. W. Negele, A. V. Pochinsky, M. Procura, M. Engelhardt, Ph. Hagler, T. R. Hemmert, W. Schroers

摘要:

本文利用精细格点上的畴壁夸克,对$N_f=2+1$格点量子色动力学中的核子电磁形状因子进行了高统计计算,使系统误差和统计误差的计算精度达到新的水平.我们的计算使用$32^3 \times 64$晶格与晶格间距a=0.084 fm的π介子质量为297,355,和403 MeV,我们进行了超定分析,使用的顺序为3600至7000测量计算核子的电磁形状因子高达$Q^2 \approx$ 1.05 GeV $^2$。结果表明,与使用价畴壁夸克与改进的交错海夸克,并使用粗畴壁晶格得到的结果是一致的。我们确定了等矢量狄拉克半径$r_1^v$、泡利半径$r_2^v$和反常磁矩$κ_v$。我们还确定连接的贡献,相应的isoscope观测。我们外推这些观测到的物理π介子质量使用两种不同的配方的双味手征有效场论在一个循环:重子小尺度展开(SSE)和协变重子手征微扰理论。的isovector结果和连接的贡献的isoscillation结果与实验进行了比较,并讨论了在较小的π介子质量的计算的必要性。

英文摘要:

We present a high-statistics calculation of nucleon electromagnetic form factors in $N_f=2+1$ lattice QCD using domain wall quarks on fine lattices, to attain a new level of precision in systematic and statistical errors. Our calculations use $32^3 \times 64$ lattices with lattice spacing a=0.084 fm for pion masses of 297, 355, and 403 MeV, and we perform an overdetermined analysis using on the order of 3600 to 7000 measurements to calculate nucleon electric and magnetic form factors up to $Q^2 \approx$ 1.05 GeV$^2$. Results are shown to be consistent with those obtained using valence domain wall quarks with improved staggered sea quarks, and using coarse domain wall lattices. We determine the isovector Dirac radius $r_1^v$, Pauli radius $r_2^v$ and anomalous magnetic moment $κ_v$. We also determine connected contributions to the corresponding isoscalar observables. We extrapolate these observables to the physical pion mass using two different formulations of two-flavor chiral effective field theory at one loop: the heavy baryon Small Scale Expansion (SSE) and covariant baryon chiral perturbation theory. The isovector results and the connected contributions to the isoscalar results are compared with experiment, and the need for calculations at smaller pion masses is discussed.

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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