A degree preserving delta wye transformation with applications to 6-regular graphs and Feynman periods

TL;DR

This paper introduces a degree-preserving delta-wye transformation for 6-regular graphs, exploring its implications for Feynman integrals and graph equivalence classes, with potential applications in quantum field theory calculations.

Contribution

It develops a novel degree-preserving transformation and analyzes the structure of graph equivalence classes relevant to Feynman periods and scalar integrals in six dimensions.

Findings

Finite equivalence classes under the transformation identified.

Connections between graph structures and Feynman periods established.

Properties of minimal graphs in these classes analyzed.

Abstract

We investigate a degree preserving variant of the $\Delta$-Y transformation which replaces a triangle with a new 6-valent vertex which has double edges to the vertices that had been in the triangle. This operation is relevant for understanding scalar Feynman integrals in 6 dimensions. We study the structure of equivalence classes under this operation and its inverse, with particular attention to when the equivalence classes are finite, when they contain simple 6-regular graphs, and when they contain doubled 3-regular graphs. The last of these, in particular, is relevant for the Feynman integral calculations and we make some observations linking the structure of these classes to the Feynman periods. Furthermore, we investigate properties of minimal graphs in these equivalence classes.