An introduction to PYTHIA 8.2

This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2018)

Abstract
The Pythia program is a standard tool for the generation of events in high-energy collisions, comprising a coherent set of physics models for the evolution from a few-body hard process to a complex multiparticle final state. It contains a library of hard processes, models for initial- and final-state parton showers, matching and merging methods between hard processes and parton showers, multiparton interactions, beam remnants, string fragmentation and particle decays. It also has a set of uti...

Title of program: Pythia 8.2
Catalogue Id: ACTU_v4_0

Nature of problem
High-energy collisions between elementary particles normally give rise to complex final states, with large multiplicities of hadrons, leptons, photons and neutrinos. The relation between these final states and the underlying physics description is not a simple one, for two main reasons. Firstly, we do not even in principle have a complete understanding of the physics. Secondly, any analytical approach is made intractable by the large multiplicities.

Versions of this program held in the CPC repository in Mendeley Data
ACTU_v1_0; PYTHIA 5.7 AND JETSET 7.4; 10.1016/0010-4655(94)90132-5
ACTU_v2_0; PYTHIA V6.154; 10.1016/S0010-4655(00)00236-8
ACTU_v2_1; PYTHIA Version number: 6.420; 10.1016/j.cpc.2009.08.008
ACTU_v3_0; Pythia 8.1; 10.1016/j.cpc.2008.01.036
ACTU_v4_0; Pythia 8.2; 10.1016/j.cpc.2015.01.024

本程序源自贝尔法斯特女王大学（Queen's University Belfast）馆藏的CPC程序库（1969-2018）。

摘要
Pythia程序是用于高能碰撞事件生成的标准工具，包含一套连贯的物理模型，可描述从少体硬散射过程到复杂多粒子末态的演化历程。该程序内置硬散射过程库、初态与末态部分子喷注（parton shower）模型、硬散射过程与部分子喷注间的匹配与合并方法、多部分子相互作用、束流残余、弦碎裂以及粒子衰变模型，同时还拥有一系列应用[原文此处存在截断]。

程序名称：Pythia 8.2
目录编号：ACTU_v4_0

问题本质
基本粒子间的高能碰撞通常会产生复杂的末态，伴随大量强子、轻子、光子与中微子。这类末态与底层物理描述之间的关联并不简单，主要原因有二：其一，即便在理论层面，我们也尚未完全掌握相关物理规律；其二，末态粒子数目庞大，使得任何解析方法都难以处理。

孟德尔莱数据（Mendeley Data）的CPC程序库中收录的本程序各版本：
ACTU_v1_0；PYTHIA 5.7 与 JETSET 7.4；DOI:10.1016/0010-4655(94)90132-5
ACTU_v2_0；PYTHIA V6.154；DOI:10.1016/S0010-4655(00)00236-8
ACTU_v2_1；PYTHIA 版本号：6.420；DOI:10.1016/j.cpc.2009.08.008
ACTU_v3_0；Pythia 8.1；DOI:10.1016/j.cpc.2008.01.036
ACTU_v4_0；Pythia 8.2；DOI:10.1016/j.cpc.2015.01.024