Relativistic kinematics

  • Thread starter jdstokes
  • Start date
  • #1
523
0

Main Question or Discussion Point

Hi all,

I would be very grateful if anyone would be willing to check my understanding of this stuff as it has been several years since I used it in undergrad calculations.

If a proton and a photon collide head-on with known energies, then the energy in the center of mass frame will be given by the invariant mass [itex]E_\mathrm{com} = W[/itex]. Thus [itex]E_\mathrm{com} = \sqrt{(E_\gamma+ E_p)^2-(p_\gamma + p_p)^2} = \sqrt{(E_\gamma+ E_p)^2-\left(E_\gamma + \sqrt{E_p^2 - m_p^2}\right)^2} [/itex].

Does this sound reasonable?
 

Answers and Replies

  • #2
malawi_glenn
Science Advisor
Homework Helper
4,786
22
sure why not, remember that you should have vector p's in the first expression:

[tex]E_\mathrm{com} = \sqrt{(E_\gamma+ E_p)^2-(\vec{p}_\gamma + \vec{p}_p)^2}[/tex]

Just for completeness, then use the fact that they are 'head on'
 
  • #3
pam
455
1
That means you need a minus sign in your last term.
 

Related Threads for: Relativistic kinematics

  • Last Post
Replies
6
Views
3K
  • Last Post
Replies
15
Views
4K
  • Last Post
Replies
5
Views
873
  • Last Post
Replies
13
Views
5K
Replies
4
Views
996
Replies
1
Views
2K
  • Last Post
Replies
4
Views
1K
Replies
3
Views
1K
Top