PYTHIA Documentation

PYTHIA is documented in several ways, both online and in publications. The main reference is the PYTHIA 8.3 publication listed below.

A comprehensive guide to the physics and usage of PYTHIA 8.3 is the main reference for PYTHIA 8.3. It can be found as [arXiv:2203.11601 [hep-ph]], journal publication pending. Please see the section on citing PYTHIA for information about how to cite PYTHIA in publications.
HTML manuals: The main source of documentation is the HTML manual, which is provided with the distribution. For convenience, the HTML manuals for all versions are available online. The latest manual can always be found at this permanent link
Doxygen: Automatically generated Doxygen documentation is provided for all releases. This documentation does not replace the HTML manual. The latest doxygen representation can always be found at this permanent link.
PYTHIA 8.2 introduction, published as: An Introduction to PYTHIA 8.2, T. Sjöstrand et al, Comput. Phys.Commun. 191 (2015) 159 [arXiv:1410.3012 [hep-ph]], may still contain useful information, but is superseded by the PYTHIA 8.3 publication above.
A brief introduction to PYTHIA 8.1 may still contain useful information, but is superseeded by the publications above.
PYTHIA 6.4 physics and manual: this describes in detail the physics implemented in PYTHIA 6, and while some material may still be useful, it is superseded by the publications above.
PYTHIA 8.2 worksheet: this worksheet was developed for use at summer schools, but is also suited for self-study.

License information

PYTHIA 8 is licensed under the GNU General Public Licence version 2 or later. Please respect the MCnet Guidelines for Event Generator Authors and Users.

Citing PYTHIA

PYTHIA is the product of many years of work developing models and implementing them in an event generator. When you use PYTHIA for a publication, both the most recent PYTHIA manual (currently A comprehensive guide to the physics and usage of PYTHIA 8.3) and the paper(s) introducing the physics model you are using, must be cited. Note that in some cases the used physics models are not created by, or only partially created by, the PYTHIA authors, underlining the importance of proper citations.

In the pdf manual, as well as in the HTML manual, you can find an extensive bibliography pointing to the correct physics paper(s) to cite, in addition to the PYTHIA manual, when using PYTHIA.
If you use PYTHIA by proxy, ie. through another program which interfaces to PYTHIA, and your result relies on this interfacing, the above guideline still holds.
When using PYTHIA, always specify the full version number, and any relevant parameter modifications.
You are welcome to contact us if you are unsure what to cite in your paper.

Validation

The main publicly accessible repository of validation plots for PYTHIA 8 is the xternal MCplots web site. This contains extensive browsable validation plots for PYTHIA 8 and comparisons to other generators.

The MCplots validation site is based on the Rivet analysis preservation system and the Test4Theory project on LHC@home. If you find this resource useful, consider joining the LHC@home project as a volunteer and select the Test4Theory project. If you use results from MCplots in your work, for presentations, or in discussions, please also endeavour to cite the MCplots paper.

Note: there is normally a delay after a new PYTHIA release before it can appear on MCplots. Therefore, the PYTHIA versions shown available on MCplots are typically a few versions behind the most recent one.

HTML manuals and Doxygen

Here you can find online versions of the PYTHIA manual and a Doxygen representation of the code, dating back to Pythia 8.051, which was the first version to have a such a manual. For earlier versions in the Pythia 8 series, you have to download the code and study the contained manual.

PYTHIA Documentation

License information

Citing PYTHIA

Validation

HTML manuals and Doxygen

PYTHIA 8.3 series:

PYTHIA 8.2 series:

PYTHIA 8.1 series:

PYTHIA 8.0 series: