- #1
LAHLH
- 409
- 1
Hi,
In Srednicki's chapter on cross sections, when he calculating the probability of a particular process from the overlap [tex] \langle f\mid i\rangle[/tex] he comes across:
[tex] [(2\pi)^4\delta^4(k_{in}-k_{out})]^2 [/tex]
He states this is can be equated as follows: [tex] [(2\pi)^4\delta^4(k_{in}-k_{out})]^2= (2\pi)^4\delta^4(k_{in}-k_{out})\times (2\pi)^4\delta^4(0) [/tex]
I presume from the rest of the text that he is evaluating this as if it was being integrated over $k$, but I still can't see where this comes from. I've tried google but all I seem to find is a lot of discussion about people not being sure if the square of the delta function is even well defined.
Thanks
In Srednicki's chapter on cross sections, when he calculating the probability of a particular process from the overlap [tex] \langle f\mid i\rangle[/tex] he comes across:
[tex] [(2\pi)^4\delta^4(k_{in}-k_{out})]^2 [/tex]
He states this is can be equated as follows: [tex] [(2\pi)^4\delta^4(k_{in}-k_{out})]^2= (2\pi)^4\delta^4(k_{in}-k_{out})\times (2\pi)^4\delta^4(0) [/tex]
I presume from the rest of the text that he is evaluating this as if it was being integrated over $k$, but I still can't see where this comes from. I've tried google but all I seem to find is a lot of discussion about people not being sure if the square of the delta function is even well defined.
Thanks