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Do Feynman diagrams that have at least one line/propogator that begins and ends on the same space-time point have a special name? For example, the "cactus" diagram from the bottom of page 92 in "An Introduction to Quantum Field Theory" by Peskin and Schroeder qualifies. These are the diagrams that will have factors of $G(0)$ in them, where $G\left(\tau = \sqrt{\left(c\Delta t\right)^2 - \left|\Delta \vec{r}\right|^2}\right)$ is the propagator.

I ask because it seems that calling them ouroboros diagrams, for the snake that eats its own tail, would be fittingly poetic, but am unsure if this or another name had already been coined.

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I believe in Mike Stone's The Physics of Quantum Fields they are called just that.

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