GoSam: A program for automated one-loop Calculations

TL;DR

GoSam is an automated software tool designed to efficiently compute one-loop amplitudes for complex multi-particle processes in particle physics, supporting various reduction methods and theories beyond the Standard Model.

Contribution

It introduces a flexible, automated framework for calculating one-loop amplitudes, integrating multiple reduction techniques and extending support to BSM theories.

Findings

Successfully computes one-loop corrections for QCD and electroweak processes.

Supports models beyond the Standard Model.

Demonstrated versatility through various example calculations.

Abstract

The program package GoSam is presented which aims at the automated calculation of one-loop amplitudes for multi-particle processes. The amplitudes are generated in terms of Feynman diagrams and can be reduced using either D-dimensional integrand-level decomposition or tensor reduction, or a combination of both. GoSam can be used to calculate one-loop corrections to both QCD and electroweak theory, and model files for theories Beyond the Standard Model can be linked as well. A standard interface to programs calculating real radiation is also included. The flexibility of the program is demonstrated by various examples.