content_image/311459.jpg content_image/311460.jpg
A useful relation comes from eikonality: 

<img src='content_image/311459.jpg'>

## E.2 Monojet vs. Dijet 0 th Order Radiation 

In order to motivate the work of Appendix F we will derive the 0 th order bremsstrahlung radiation loss for massive quarks and gluons using two meth- ods and find that the results are inconsistent. We will find that the usual pQCD approach of calculating the radiation spectrum from a monojet only is consistent with a dijet calculation in the massless limit only. For massive gluons the longitudinal polarization must be considered, and its contribution to the spectrum from the away-side jet will be O (1) in an expansion in powers of 1 /E $^{+}$. 

## E.2.1 Peskin’s Trick 

We will find the following relations useful in evaluating Feynman diagrams related to bremsstrahlung, which we will refer to as Peskin’s Trick: 

<img src='content_image/311460.jpg'>

