Skip to main content

Research Repository

Advanced Search

UFO 2.0: the ‘Universal Feynman Output’ format

Darmé, Luc; Degrande, Céline; Duhr, Claude; Fuks, Benjamin; Goodsell, Mark; Heinrich, Gudrun; Hirschi, Valentin; Höche, Stefan; Höfer, Marius; Isaacson, Joshua; Mattelaer, Olivier; Ohl, Thorsten; Pagani, Davide; Reuter, Jürgen; Richardson, Peter; Schumann, Steffen; Shao, Hua-Sheng; Siegert, Frank; Zaro, Marco

UFO 2.0: the ‘Universal Feynman Output’ format Thumbnail


Luc Darmé

Céline Degrande

Claude Duhr

Benjamin Fuks

Mark Goodsell

Gudrun Heinrich

Valentin Hirschi

Stefan Höche

Marius Höfer

Joshua Isaacson

Olivier Mattelaer

Thorsten Ohl

Davide Pagani

Jürgen Reuter

Steffen Schumann

Hua-Sheng Shao

Frank Siegert

Marco Zaro


We present an update of the Universal FeynRules Output model format, commonly known as the UFO format, that is used by several automated matrix-element generators and high-energy physics software. We detail different features that have been proposed as extensions of the initial format during the last ten years, and collect them in the current second version of the model format that we coin the Universal Feynman Output format. Following the initial philosophy of the UFO, they consist of flexible and modular additions to address particle decays, custom propagators, form factors, the renormalisation group running of parameters and masses, and higher-order quantum corrections.


Darmé, L., Degrande, C., Duhr, C., Fuks, B., Goodsell, M., Heinrich, G., …Zaro, M. (2023). UFO 2.0: the ‘Universal Feynman Output’ format. The European Physical Journal C, 83(7), Article 631.

Journal Article Type Article
Acceptance Date Jun 28, 2023
Online Publication Date Jul 17, 2023
Publication Date Jul 17, 2023
Deposit Date Feb 12, 2024
Publicly Available Date Feb 12, 2024
Journal The European Physical Journal C
Print ISSN 1434-6044
Publisher SpringerOpen
Peer Reviewed Peer Reviewed
Volume 83
Issue 7
Article Number 631
Keywords Physics and Astronomy (miscellaneous); Engineering (miscellaneous)
Public URL


Published Journal Article (648 Kb)


Publisher Licence URL

Copyright Statement
This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit

You might also like

Downloadable Citations