CHY-Graphs on a Torus

TL;DR

This paper advances the CHY framework for one-loop scattering amplitudes on elliptic curves by introducing connectors and rules to construct integrands, demonstrated through $ ext{Phi}^3$ scalar theory calculations.

Contribution

It develops a new method to build integrands on elliptic moduli space from sphere integrands, enabling systematic computation of one-loop diagrams.

Findings

Introduced connectors for integrand construction on $rak{M}_{1,n}$

Established rules to derive elliptic integrands from sphere integrands

Successfully computed various one-loop Feynman diagrams in $ ext{Phi}^3$ theory

Abstract

Recently, we proposed a new approach using a punctured Elliptic curve in the CHY framework in order to compute one-loop scattering amplitudes. In this note, we further develop this approach by introducing a set of connectors, which become the main ingredient to build integrands on $\mathfrak{M}_{1,n}$, the moduli space of n-punctured Elliptic curves. As a particular application, we study the $\Phi^3$ bi-adjoint scalar theory. We propose a set of rules to construct integrands on $\mathfrak{M}_{1,n}$ from $\Phi^ 3$ integrands on $\mathfrak{M}_{0,n}$, the moduli space of n-punctured spheres. We illustrate these rules by computing a variety of $\Phi^3$ one-loop Feynman diagrams. Conversely, we also provide another set of rules to compute the corresponding CHY-integrand on $\mathfrak{M}_{1,n}$ by starting instead from a given $\Phi^ 3$ one-loop Feynman diagram. In addition, our results can easily be extended to higher loops.