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View Full Version : Why is counterm included in both orders of correction in Srednicki chapter 14


LAHLH
Mar4-10, 09:08 AM
Hi,

I think maybe my last question was too much of an essay for anybody to bother going through, so I thought I would ask something more modest:

In Srednicki chapter 14 fig 14.1, we have the counterm correction from A and B contributing to O(g^2), I understand it being here since A,B themselves are of O(g^2) so of course the 2 valent vertex they create is of this order in that diagram.

However Srednicki also includes this exact same diagram as his rightmost diagram for the ones contributing to O(g^4) aswell, how can it possibly be both orders?

Thanks again for any help, I really appreciate it. (this book is free to download on his webpage btw for anyone interested)