Can anyone recommend references for four particle production calculations?

[kaksmet]

Hey!

I am doing some tree level calculations of production of four final leptons and have some trouble with the kinematics. Does anybody know any good references where to read up a bit this topic and/or good variables/frames to use in order for the description to be as easy as possible? My problem is to choose a frame/variables where I can find a resonably simple description of the matrix element and also solve the phase-space integrals.

A typical process would be
e+ e- --> gamma --> W+ W- --> e+ e- anti-v v

Thanks a lot!

 

[Vanadium 50]

Why not just use the zero width approximation and do it in pieces? (i.e. decay the W's independently)

 

[kaksmet]

Why not just use the zero width approximation and do it in pieces? (i.e. decay the W's independently)

Maybe.. can you direct me to any place where I can find out more about what that is?
Thanks

 

[Navir]

Vanadium 50 is talking about Narrow Width Approximation. Check for example arXiv:0807.4112v2. If you'll need any help with that just ask.

 

[kaksmet]

Vanadium 50 is talking about Narrow Width Approximation. Check for example arXiv:0807.4112v2. If you'll need any help with that just ask.

Thank you, will take a closer look at that but a first thought is that it cannot help me with the problem at hand because I want to be able to have a calculation which is valid also if one of the W is interchanged with the gamma.. and the gamma can not be on shell..