Calculating multileg one-loop processes. The case of gg -> t bar_t+gg

TL;DR

This paper presents a computational framework for calculating next-to-leading order (NLO) corrections to complex multileg processes at the LHC, focusing on gg -> t t̄ + gg, using automated Fortran code generation.

Contribution

It introduces a method for analytical reduction of one-loop integrals and automated code generation for NLO corrections in multileg processes.

Findings

Efficient reduction of one-loop integrals to scalar master integrals.

Automated Fortran code for numerical NLO calculations.

Application to gg -> t t̄ + gg process at the LHC.

Abstract

This study is targeted to the NLO corrections of multileg processes, very important for the LHC. Starting from the construction of Feynman diagrams, the analytical reduction of general one-loop integrals to scalar master ones, the calculation of color structures, manipulation of spinor lines and other amplitude constituents and finally phase space point selection are obtained by use of a program producing Fortran code for numerical calculation of one-loop corrections for processes like gg -> t bar_t+gg.