# Homework Help: Particle collision/decay in CM frame

1. Feb 18, 2010

### wakko101

1. The problem statement, all variables and given/known data

Consider the process, in the lab, (K plus)(proton) to (K plus)(Pion neutral)(proton). The final state of K has a momentum of 5GeV/c and the pion has a momentum of 4 GeV/c and the angle between them is 7.3 degrees. The first part asks to calculate the invariant mass of the (K plus)(pion), which I've done.

A subsequent part asks: Assume that the (K plus)(pion) comes from an intermediate state, and that the beam energy in this experiment is 20 GeV. Calculate the momentum of the final state proton in the CM frame

2. Relevant equations

Not sure at this point...

3. The attempt at a solution

I think that I've been thinking about this question so long, I"ve managed to completely screw up my brain about it. I'm not sure if I should be using 4 momentum or invariant mass or energy equations or what to do. If someone simply had a suggestion as to where I begin, that would be great!

Cheers,
W. =)

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted