arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0712.2670hep-ph
收藏

与碰撞参量相关的有色玻璃凝聚偶极子模型

Impact parameter dependent colour glass condensate dipole model

G. Watt, H. Kowalski

摘要:

我们表明,Iancu,Itakura和Munier的彩色玻璃凝聚偶极子模型,改进,包括碰撞参量的依赖,给出了一个很好的拟合总伽玛 * p截面在HERA测量,如果在饱和标度,gamma_s,被视为一个自由参数的异常尺寸。我们发现最佳γ_s = 0.46与Balitsky-Kovchegov方程数值解所确定的值接近。对于最相关的碰撞参量b ~ 2-3 GeV^{-1},HERA运动学区域中与碰撞参量相关的饱和标度通常小于0.5 GeV ^2。我们比较预测的模型的数据上的纵向和重味结构功能,独家衍射矢量介子生产和深深的虚拟康普顿散射在HERA。该模型被发现是不足的观测灵敏度适中的小偶极子的大小,其中一个替代模型与明确的DGstrom演化表现更好。排他性的衍射过程的能量依赖性示出提供不同的偶极子模型截面之间的一个重要的转换。

英文摘要:

We show that the colour glass condensate dipole model of Iancu, Itakura and Munier, improved to include the impact parameter dependence, gives a good fit to the total gamma* p cross section measured at HERA if the anomalous dimension at the saturation scale, gamma_s, is treated as a free parameter. We find that the optimum value of gamma_s = 0.46 is close to the value determined from numerical solution of the Balitsky-Kovchegov equation. The impact parameter dependent saturation scale is generally less than 0.5 GeV^2 in the HERA kinematic regime for the most relevant impact parameters b ~ 2-3 GeV^{-1}. We compare predictions of the model to data on the longitudinal and heavy flavour structure functions, exclusive diffractive vector meson production and deeply virtual Compton scattering at HERA. The model is found to be deficient for observables sensitive to moderately small dipole sizes, where an alternative model with explicit DGLAP evolution performs better. The energy dependence of exclusive diffractive processes is shown to provide an important discriminator between different dipole model cross sections.

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。

↑