Lab frame versus center of momentum frame

Click For Summary
SUMMARY

The discussion focuses on the analysis of Compton scattering in the lab frame versus the center of momentum (CM) frame. It highlights that while the CM frame is often preferred for theoretical analysis due to convenience, experimental measurements are typically conducted in the lab frame. The conversation also addresses the challenge of converting cross-sections from the CM frame to the lab frame, emphasizing the use of Mandelstam variables for this purpose. The participants confirm that while stationary muons can be analyzed, practical considerations often dictate the choice of frame.

PREREQUISITES
  • Understanding of Compton scattering and its significance in particle physics.
  • Familiarity with the concepts of lab frame and center of momentum frame.
  • Knowledge of Feynman diagrams and amplitudes in quantum field theory.
  • Proficiency in using Mandelstam variables for kinematic calculations.
NEXT STEPS
  • Study the conversion of cross-sections between the center of momentum frame and the lab frame.
  • Learn about the application of Mandelstam variables in particle collision analyses.
  • Explore the theoretical underpinnings of Compton scattering in different reference frames.
  • Investigate experimental setups for colliding electrons with stationary muons.
USEFUL FOR

Physicists, particularly those specializing in particle physics, experimental researchers, and students studying relativistic collisions and scattering processes.

jdstokes
Messages
520
Reaction score
1
Why is it conventional to analyse compton scattering in the lab frame (fixed target) whereas all other processes I've seen are analysed in the center of momentum (colliding beam) frame.

Are there any experiments where one would collide electrons with stationary muons e.g.?
 
Physics news on Phys.org
Convenience, mostly.

To answer your second question, how do you get stationary muons?
 
It is often far easier to analyze things in the center of mass frame. The measurement equipment, however, is in the lab frame, so at some point the results of the analysis have to be recast to the lab frame.
 
If the electrons are relativistic then muons confined by electric of magnetic fields could be considered at rest?
 
So If I calculate a cross-section in the center of mass frame, is there any way of converting this directly to a Lab cross-section, or do I have to go back to the Feynman amplitude for the process and redo the kinematics at that point.
 
You can usually write a cross-section formula in terms of invariants times simple kinematic factors, making going between the cm and the lab relatively easy.
 
Ahh yes, the old Mandelstam variables, good point.
 

Similar threads

  • · Replies 9 ·
Replies
9
Views
1K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 14 ·
Replies
14
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 12 ·
Replies
12
Views
3K
Replies
4
Views
3K
  • · Replies 0 ·
Replies
0
Views
4K
  • · Replies 7 ·
Replies
7
Views
2K