Nikhef and Department of Physics and Astronomy, VU University Amsterdam, De Boelelaan 1081, NL-1081 HV Amsterdam, The Netherlands.
Phys Rev Lett. 2014 Mar 7;112(9):092002. doi: 10.1103/PhysRevLett.112.092002. Epub 2014 Mar 3.
In the resummation of collinear gluons emitted together with active partons from the hadrons in the Drell-Yan process, effects of color entanglement become important when the transverse directions are taken into account. It is then no longer possible to write the cross section as the convolution of two soft correlators and a hard part. We show that the color entanglement introduces additional color factors that must be taken into account in the extraction of transverse momentum-dependent parton distribution functions from azimuthal asymmetries. Examples where such effects matter are the extractions of the double Sivers and double Boer-Mulders asymmetries. Furthermore, we will argue why this color entanglement is a basic ingredient already in the tree-level description of azimuthal asymmetries.
在 Drell-Yan 过程中，从强子中一起发射的共线胶子的重求和，当考虑横向方向时，颜色纠缠的影响变得很重要。在这种情况下，不再可能将横截面写成两个软关联函数和一个硬部分的卷积。我们表明，颜色纠缠引入了额外的颜色因子，这些因子在从方位不对称中提取横向动量相关部分子分布函数时必须考虑。这种效应重要的例子是双 Sivers 和双 Boer-Mulders 不对称的提取。此外，我们将论证为什么这种颜色纠缠已经是方位不对称的树级描述的基本成分。
