One-loop N = 4 super Yang-Mills scattering amplitudes in d dimensions, relation to open strings and polygonal Wilson loops

TL;DR

This paper explores the detailed structure of one-loop N=4 super Yang-Mills scattering amplitudes in various dimensions, revealing their relation to string theory corrections and providing new all-orders-in-epsilon results for specific six-particle amplitudes.

Contribution

It introduces new all-orders-in-epsilon superamplitude formulas for six-particle NMHV scattering and links gauge theory amplitudes to string corrections, advancing understanding of supersymmetric scattering.

Findings

Higher order epsilon contributions are useful beyond the epsilon^0 limit.

Derived a new all-orders-in-epsilon superamplitude for six-particle NMHV scattering.

Established a relation between super Yang-Mills amplitudes and stringy corrections.

Abstract

In this review we discuss some recent developments related to one-loop N = 4 super Yang-Mills scattering amplitudes calculated to all orders in epsilon. It is often the case that one-loop gauge theory computations are carried out to order epsilon^0, since higher order in epsilon contributions vanish in the limit as epsilon goes to zero. We will show, however, that the higher order contributions are actually quite useful. In the context of maximally supersymmetric Yang-Mills, we consider two examples in detail to illustrate our point. First we concentrate on computations with gluonic external states and argue that N = 4 supersymmetry implies a simple relation between all-orders-in-epsilon one-loop N = 4 super Yang-Mills amplitudes and the first and second stringy corrections to analogous tree-level superstring amplitudes. For our second example we will derive a new result for the all-orders-in-epsilon one-loop superamplitude for planar six-particle NMHV scattering, an object which allows one to easily obtain six-point NMHV amplitudes with arbitrary external states. We will then discuss the relevance of this computation to the evaluation of the ratio of the planar two-loop six-point NMHV superamplitude to the planar two-loop six-point MHV superamplitude, a quantity which is expected to have remarkable properties and has been the subject of much recent investigation.