Scheme invariants in phi^4 theory in four dimensions

Understand

We provide an analysis of the structure of renormalisation scheme invariants for the case of $\phi^4$ theory, relevant in four dimensions.

• We give a complete discussion of the invariants up to four loops and include some partial results at five loops, showing that there are considerably more invariants than one might naively have expected.
• We also show that one-vertex reducible contributions may consistently be omitted in a well-defined class of schemes which of course includes MSbar.