HELAC: A package to compute electroweak helicity amplitudes

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)

**摘要**
HELAC是一款基于FORTRAN语言的软件包，可在标准电弱理论（standard electroweak theory）框架下，高效计算任意散射过程的螺旋度振幅（helicity amplitudes）。相较于传统的费曼图方法（Feynman graph approach），该算法充分利用了戴森-施温格方程（Dyson–Schwinger equations）的优势。程序囊括幺正规范与费曼规范下的全部电弱相互作用顶点（electroweak vertices），且支持包含所有质量效应的计算。此外还提供了支持任意用户自定义精度的多精度计算版本……（原文此处存在截断）

**程序名称**：HELAC
**目录编号**：ADMS_v1_0

**问题本质**
当前粒子现象学的绝大多数研究，均依赖于我们对涉及较多粒子数的物理过程开展高效研究的能力。这就需要能够高效计算矩阵元（matrix element）、生成相空间（phase space）并完成积分的算法。就矩阵元计算而言，传统方法采用散射振幅的标准费曼图表示，其计算成本随粒子数n呈阶乘级渐近增长，其中……（原文此处存在截断）

**曼德列数据（Mendeley Data）中收录的该程序版本**
ADMS_v1_0; HELAC; 10.1016/S0010-4655(00)00151-X
ADMS_v2_0; HELAC-PHEGAS; 10.1016/j.cpc.2009.04.023

**本程序源自贝尔法斯特女王大学托管的CPC程序库（1969-2019）**