Pseudo-Evanescent Feynman Integrals from Local Subtraction

We introduce a new approach for the computation of the class of Feynman integrals whose integrands vanish in strictly four-dimensions, so-called ''pseudo-evanescent'' integrals. We argue that, up to $\mathcal{O}(\epsilon)$ corrections, local subtraction techniques can be used to express pseudo-evanescent integrals in terms of contributions from infrared and ultraviolet regions of loop-momentum space. We study two-loop examples and find that many pseudo-evanescent Feynman integrals are reduced to either products of one-loop integrals or one-fold integrals thereof. As a demonstration of the power of our approach, we use it to recompute the two-loop all-plus five-point amplitude. We find that, up to scheme-dependent logarithms, all contributions from soft and collinear regions cancel exactly against known infrared structure and that the finite remainder is entirely given by contributions from ultraviolet regions.