# HELAC: A package to compute electroweak helicity amplitudes

## Description

Abstract HELAC is a FORTRAN based package that is able to compute efficiently helicity amplitudes for arbitrary scattering processes within the standard electroweak theory. The algorithm exploits the virtues of the Dyson–Schwinger equations as compared to the traditional Feynman graph approach. All electroweak vertices are included in both the unitary and Feynman gauges, and computations including all mass effects are available. A version performing multi-precision computations with arbitrary – user d... Title of program: HELAC Catalogue Id: ADMS_v1_0 Nature of problem A substantial part of particle phenomenology nowadays is based upon our ability to study efficiently processes involving a relatively large number of particles. This requires efficient algorithms for matrix element calculation and phase space generation and integration. As far as the matrix element calculation is concerned, the traditional approach utilizes standard Feynman graph representation of the scattering amplitude, resulting to a computational cost that grows asymptotically as n!, where ... Versions of this program held in the CPC repository in Mendeley Data ADMS_v1_0; HELAC; 10.1016/S0010-4655(00)00151-X ADMS_v2_0; HELAC-PHEGAS; 10.1016/j.cpc.2009.04.023 This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2019)