e-A深度非弹性散射中胶子辐射振幅的新计算方法

在e-A深度非弹性散射过程中, 喷注穿过冷核介质时, 多重散射诱导胶子辐射会导致对碎裂函数的修正及喷注的能量损失.前期研究中关于计算e-A深度非弹性散射中胶子辐射振幅的两种方法: 螺旋振幅近似和微扰QCD严格计算都异常繁杂. 本文发展了一种新的方法, 可以方便计算出多重散射导致胶子辐射的振幅, 得到的碎裂函数的修正以及能量损失与严格计算的结果一致.

A New Calculational Approach to the Amplitude of Gluon Radiation in e-A DIS

In the deeply inelastic e-A scattering, the gluon radiation induced by multiple scattering will lead to medium modification of the parton fragmentation functions and also associate with the energy loss of the leading quark. To obtain the hard partonic part of quark-gluon double scattering, one can do a complete calculation within the framework of generalized factorization in perturbative QCD. In another way one can utilize the approach of helicity amplitude approximation(HAA) to calculate the amplitude of gluon radiation. However, the two methods are both complicated and tedious. In this paper, we will introduce a new approach which enables one to calculate easily the amplitude for gluon radiation in multiple scattering. The final results obtained by using our new approach agree exactly with the complete calculation in perturbative QCD.