- #1
gobbles
- 17
- 1
Wherever I see calculations of two-loop contributions to the ##\phi^4## propagator (such as Peskin, page 328, on the bottom), only the sunset diagram (aka the Saturn diagram) is considered, but not, say, the two-loop diagram involving a loop on top of a loop (looks like this: _8_). Does it not contribute? As far as I can tell, it does and the expression for it is
##\int\frac{d^4k}{k^2-m^2}\frac{d^4q}{q^2-m^2}##
with a high degree of divergence (##\Lambda^4##). Am I correct?
##\int\frac{d^4k}{k^2-m^2}\frac{d^4q}{q^2-m^2}##
with a high degree of divergence (##\Lambda^4##). Am I correct?