arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1111.0463hep-ph
收藏

单规范玻色子交换近似下的领先核子形状因子

Leading Nucleon Form Factors in Single Gauge Boson Exchange Approximation

Thorsten Sachs, Patrick Sturm

摘要:

在大动量转移和单规范玻色子交换近似下,我们给出了所有领先核子形状因子的完整计算。为了计算所需的核子跃迁几率矩阵元,我们将QCD微扰理论与核子分布振幅展开相结合。仅用领先的扭曲核子分布振幅,就可得到所需的核子形状因子。当分布振幅采用三阶多项式,系数采用非微扰模型时,所得结果与实验数据一致。最后,我们比较了我们的结果的狄拉克形状因子的质子与以前的结果的基础上的QCD因式分解定理,其中正确的对称性因子的差异仍在讨论中。我们检查了计算结果并提出了解释。

英文摘要:

We provide a complete calculation of all leading nucleon form factors at large momentum transfer and in single gauge boson exchange approximation. In order to evaluate the required nucleon transition probability matrix elements, we combine QCD perturbation theory with an expansion in nucleon distribution amplitudes. Using leading twist nucleon distribution amplitudes only, one obtains the desired nucleon form factors. The obtained results are consistent with experimental data when we use third order polynomials for the distribution amplitudes and non-perturbative models for the coefficients. Finally, we compare our results for the Dirac form factor of the proton with previous results based on the QCD factorization theorem, where a discrepancy about the correct symmetry factor is still under discussion. We examine the calculations and propose an explanation.

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。

↑