- #1
JohnPhys
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Hey All,
A fellow grad student and I have been working our way through Peskin & Schroeder's QFT book (not for a course), & we seem to have hit a snag in chapter 6.
Has anyone worked through the details of how to complete the angular part of the integral on page 201 that leads to Eq. 6.70? Can anyone point me in the right direction?
Particularly, I'm wondering how to go from
[tex] \int_0^1 d\xi \int \frac{d\Omega_k}{4\pi}\frac{1}{\left[\xi \hat{k} \cdot p^{\prime} + (1 - \xi) \hat{k} \cdot p \right]^2}[/tex]
to
[tex]
\int_0^1 d\xi \frac{1}{\left[\xi p^{\prime} + (1- \xi) p\right]^2}
[/tex]
It *looks* like they just assumed that the angle between k and p as well as k and p' is the same, but I can't think of a way to justify that.
What am I missing?
Any help would be greatly appreciated.
EDIT: I've noticed this has gotten a decent amount of views, with no replies! Should this be in a different forum? Do I need to supply more info? Just let me know. Thanks!
--John
A fellow grad student and I have been working our way through Peskin & Schroeder's QFT book (not for a course), & we seem to have hit a snag in chapter 6.
Has anyone worked through the details of how to complete the angular part of the integral on page 201 that leads to Eq. 6.70? Can anyone point me in the right direction?
Particularly, I'm wondering how to go from
[tex] \int_0^1 d\xi \int \frac{d\Omega_k}{4\pi}\frac{1}{\left[\xi \hat{k} \cdot p^{\prime} + (1 - \xi) \hat{k} \cdot p \right]^2}[/tex]
to
[tex]
\int_0^1 d\xi \frac{1}{\left[\xi p^{\prime} + (1- \xi) p\right]^2}
[/tex]
It *looks* like they just assumed that the angle between k and p as well as k and p' is the same, but I can't think of a way to justify that.
What am I missing?
Any help would be greatly appreciated.
EDIT: I've noticed this has gotten a decent amount of views, with no replies! Should this be in a different forum? Do I need to supply more info? Just let me know. Thanks!
--John
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