Dispersion analysis of the nucleon form factors including meson continua
Dispersion analysis of the nucleon form factors including meson continua
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DOI：
10.1103/physrevc.75.035202
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发表时间：
2006-08
影响因子：
3.1
通讯作者：
M. Belushkin;H. Hammer;U. Meissner
中科院分区：
文献类型：
--
作者：
M. Belushkin;H. Hammer;U. Meissner
色散关系为分析所有动量转移时核子的电磁形状因子提供了一个强有力的工具。介子-核子散射数据、一元性和微扰量子色动力学(QCD)的约束可以以一种直接的方式包括在内。特别是，我们在分析中包括了2{pi}、{rho}{pi}和KK连续分布作为独立的输入，并为我们的结果提供了误差范围。此外，我们还讨论了两种不同的方法来包含微扰QCD的渐近约束。我们同时分析了类空区域和类时区域中所有四个形状因子的世界数据，并总体上发现与数据很好地吻合。我们还提取了核子半径和{omega}NN耦合常数。对于半径，我们发现除了质子的电荷半径较小外，其他测定结果与其他测定结果符合得很好。通过拟合可以较好地确定{omega}NN矢量耦合常数，但对于张量耦合常数，甚至连符号都不能确定。
Dispersion relations provide a powerful tool to analyze the electromagnetic form factors of the nucleon for all momentum transfers. Constraints from meson-nucleon scattering data, unitarity, and perturbative quantum chromodynamics (QCD) can be included in a straightforward way. In particular, we include the 2{pi},{rho}{pi}, and KK continua as independent input in our analysis and provide an error band for our results. Moreover, we discuss two different methods to include the asymptotic constraints from perturbative QCD. We simultaneously analyze the world data for all four form factors in both the spacelike and timelike regions and generally find good agreement with the data. We also extract the nucleon radii and the {omega}NN coupling constants. For the radii, we generally find good agreement with other determinations with the exception of the electric charge radius of the proton, which comes out smaller. The {omega}NN vector coupling constant is determined relatively well by the fits, but for the tensor coupling constant even the sign cannot be determined.