- #1
LAHLH
- 409
- 1
Hi,
could anyone explain to me why in effective field theory (as in ch29 srednicki), you look at diagrams with only [tex]k<\Lambda[/tex] as external lines and [tex]k>\Lambda[/tex] for your interal lines? why do these diagrams with say, 6 external legs of this type, equate to the constant [tex] c_6 [/tex] say? In previous chapters of the book it's usually the exact 6 point vertex function that would equate to such a diagram, not the 6 point coupling constant itself etc.
I understand the math behind what Srednicki is doing, but not sure I understand what he is actually trying to do here, so all comments on this whole topic in QFT would be great.
thanks
could anyone explain to me why in effective field theory (as in ch29 srednicki), you look at diagrams with only [tex]k<\Lambda[/tex] as external lines and [tex]k>\Lambda[/tex] for your interal lines? why do these diagrams with say, 6 external legs of this type, equate to the constant [tex] c_6 [/tex] say? In previous chapters of the book it's usually the exact 6 point vertex function that would equate to such a diagram, not the 6 point coupling constant itself etc.
I understand the math behind what Srednicki is doing, but not sure I understand what he is actually trying to do here, so all comments on this whole topic in QFT would be great.
thanks