Recola2: REcursive Computation of One-Loop Amplitudes 2

TL;DR

Recola2 is a Fortran95 software tool that automates the calculation of next-to-leading-order amplitudes in the Standard Model and extended Higgs sectors, supporting various models and renormalization schemes.

Contribution

It introduces Recola2, a new version with extended model support, automation, and flexibility for NLO amplitude computations in particle physics.

Findings

Supports models like Two-Higgs-Doublet and Higgs-Singlet.

Automates polarized and squared amplitude calculations.

Provides color- and spin-correlated amplitudes for subtraction formalism.

Abstract

We present the Fortran95 program Recola2 for the perturbative computation of next-to-leading-order transition amplitudes in the Standard Model of particle physics and extended Higgs sectors. New theories are implemented via model files in the 't Hooft-Feynman gauge in the conventional formulation of quantum field theory and in the Background-Field method. The present version includes model files for the Two-Higgs-Doublet Model and the Higgs-Singlet Extension of the Standard Model. We support standard renormalization schemes for the Standard Model as well as many commonly used renormalization schemes in extended Higgs sectors. Within these models the computation of next-to-leading-order polarized amplitudes and squared amplitudes, optionally summed over spin and colour, is fully automated for any process. Recola2 allows the computation of colour- and spin-correlated leading-order squared amplitudes that are needed in the dipole subtraction formalism. Recola2 is publicly available for download at http://recola.hepforge.org.