Numerical evaluation of one-loop QCD amplitudes

TL;DR

This paper introduces NGluon, a program for numerically evaluating one-loop QCD amplitudes, extending its capabilities to include massless quark pairs, with detailed validation and accuracy analysis.

Contribution

The paper extends the NGluon program to handle one-loop amplitudes with massless quark pairs, providing detailed algorithmic differences and validation methods.

Findings

Successful implementation of quark pair inclusion

Validation through cross checks confirms accuracy

Numerical stability and precision analyzed extensively

Abstract

We present the publicly available program NGluon allowing the numerical evaluation of primitive amplitudes at one-loop order in massless QCD. The program allows the computation of one-loop amplitudes for an arbitrary number of gluons. The focus of the present article is the extension to one-loop amplitudes including an arbitrary number of massless quark pairs. We discuss in detail the algorithmic differences to the pure gluonic case and present cross checks to validate our implementation. The numerical accuracy is investigated in detail.