In the context of Renormalized Pertubation Theory Peskin Schröder says:
The Lagrangian
L=12(∂μϕr)2−12m2ϕ2r−λ4!ϕ4r+12δZ(∂μϕr)2−12δ2mϕ2r−δλ4!ϕ4r
gives the following set of Feynman rules:
------------>------------ =
ip2−m2+iϵ
------------X------------ =
i(p2δZ−δm)
and the two 4-vertices.
The question is: Why look the Feynman rules for the first and the fourth term of the Lagrangian look so different? I believe the answer is connected to the fact that one has to bring the kinetic term of the Lagrangian to its canonical form
12(∂μϕr)2 and has to interpret everything else as (possibly momentum dependent) vertices. How does this look in formulae?
This post imported from StackExchange Physics at 2014-06-06 20:05 (UCT), posted by SE-user quan