Quick question on Fermi Golden Rule

  • #1
1,728
13

Main Question or Discussion Point

Adopted from my lecture notes, found it a little fishy:

e7c84j.png


Shouldn't ##\frac{dp}{dE} = \frac{E}{p}## given that ##p = \sqrt{E^2 - m^2}##. Then the relation should be instead:

[tex]\frac{dp}{dE} = \frac{E}{p} = \frac{E}{\sqrt{E^2 - m^2}}[/tex]
 

Answers and Replies

  • #2
470
58
Yes, you are right but the problem tells you that B and C are massless. This means that the magnitude of their momenta is equal to their energies. In particular, conservation of energy tells you that ##E_B=E_C=E_A/2## and so ##p_B=p_C=E_A/2##, giving ##dp_B/dE=1/2##.
 
  • #3
1,728
13
Yes, you are right but the problem tells you that B and C are massless. This means that the magnitude of their momenta is equal to their energies. In particular, conservation of energy tells you that ##E_B=E_C=E_A/2## and so ##p_B=p_C=E_A/2##, giving ##dp_B/dE=1/2##.
And I suppose ##c=1##?
 
  • #4
470
58
Exactly.
 

Related Threads on Quick question on Fermi Golden Rule

Replies
1
Views
1K
  • Last Post
Replies
7
Views
2K
Replies
0
Views
1K
  • Last Post
Replies
3
Views
9K
Replies
1
Views
1K
  • Last Post
Replies
2
Views
5K
Replies
2
Views
3K
Replies
1
Views
2K
  • Last Post
Replies
3
Views
2K
Top