PYTHIA 8 Authors and Contributors

Note: prospective new contributors should consult the Code contributions section on the Contact page.

Definitions of the responsibilities of Authors, Former Authors, Contributors, etc, can be found in the Guidelines for PYTHIA Authors and Contributors.

Collaboration board

While the authors (see below) are responsible for making any important decisions, a collaboration board is in place for regular tasks. Members of the collaboration board are up for election at the yearly in-person meeting. The collaboration board currently consists of: Christian Bierlich, Ilkka Helenius, Philip Ilten, Leif Lönnblad (spokesperson), Christian T Preuss.

Contact information can be found below.

Current Authors

The PYTHIA 8.317 authors are:

• Javira Altmann, School of Physics and Astronomy, Monash University, PO Box 27, 3800 Melbourne, Australia.
• Christian Bierlich, Department of Physics, Lund University, Box 118, SE-221 00, Lund, Sweden.
• Naomi Cooke, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom
• Nishita Desai, Department of Theoretical Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India.
• Ilkka Helenius, Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland.
• Philip Ilten, Department of Physics, University of Cincinnati, Cincinnati, OH 45221, USA.
• Joni Laulainen, Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland.
• Leif Lönnblad Department of Physics, Lund University, Box 118, SE-221 00, Lund, Sweden.
• Stephen Mrenna, Computing Division, Simulations Group, Fermi National Accelerator Laboratory, MS 234, Batavia, IL 60510, USA.
• Christian T Preuss, Department of Physics, University of Wuppertal, 42119 Wuppertal, Germany.
• Torbjörn Sjöstrand Department of Physics, Lund University, Box 118, SE-221 00, Lund, Sweden.
• Peter Skands, School of Physics and Astronomy, Monash University, PO Box 27, 3800 Melbourne, Australia.

Former authors

Stefan Ask, Jesper Roy Christiansen, Richard Corke, Nadine Fischer, Leif Gellersen, Christine O. Rasmussen, Stefan Prestel, Marius Utheim, Rob Verheyen.

Further Contributions

Note for prospective new contributors: see our Guidelines

• HepMC interface by Mikhail Kirsanov.
• Conversion of XML files to PHP ones by Ben Lloyd.
• Simple Makefile for Win32/NMAKE by Bertrand Bellenot.
• Extended Higgs sector partly implemented by Marc Montull.
• Parts of charm and bottom decay tables courtesy DELPHI and LHCb collaborations.
• Tunes and comparisons with data, based on Rivet and Professor, by Hendrik Hoeth.
• Text and code on the use of ROOT in conjunction with PYTHIA by Rene Brun, Andreas Morsch and Axel Naumann.
• Code and data for MRST/MSTW PDFs by Robert Thorne and Graeme Watt.
• Code and data for the CTEQ/CT PDFs by Joey Huston and colleagues.
• Help with implementing new proton PDFs by Tomas Kasemets.
• Code and data for Pomeron PDFs by H1 collaboration and especially Paul Newman.
• Help with implementing new Pomeron fluxes and PDFs by Sparsh Navin.
• Code for Hidden Valley developed together with Lisa Carloni.
• Code for a Kaluza-Klein electroweak gauge boson provided by Noam Hod and Mark Sutton.
• Code for equivalent photon flux around an unresolved proton by Oystein Alvestad.
• The MBR diffractive model and central diffraction by Robert Ciesielski.
• 2012 branching ratios for most light hadrons, and the tau lepton, by Anil Pratap Singh.
• The pythia8-config script has been contributed by Andy Buckley, along with many other helpful suggestions.
• Code and data for several of the NNPDF2.3 QCD+QED sets, and further later ones, provided by Juan Rojo and Stefano Carrazza.
• The fjcore code from FastJet provided by Matteo Cacciari, Gavin Salam and Gregory Soyez.
• The initial-final dipole approach has been developed and implemented by Baptiste Cabouat.
• The MixMax random number generator has been contributed by Konstantin Savvidy and George Savvidy.
• Space-time hadronic production points in string fragmentation have been studied and implemented by Silvia Ferreres-Solé.
• The code for deuteron production was tested by Sophie Baker.
• C++ interface to MG5 matrix elements by V. Hirschi with additional work by O. Mattelaer.
• Mass corrections and initial-state showers in Vincia by M. Ritzmann.
• Final-state sector showers in Vincia by J. Lopez-Villarejo.
• Helicity-dependence in Vincia by A. Larkoski.
• Interleaved resonance showers and work on MESS merging and QED+EW showers in Vincia by H. Brooks.
• Static code analysis tools provided by PVS-Studio team.

Pictures

Pictures of a selection of the PYTHIA collaborators, from some of our in-person meetings.

Pythia collaboration meeting, at CERN, 7 April 2017, as part of an MCnet meeting.

Left to right: Christian Bierlich, Nishita Desai, Ilkka Helenius, Torbjörn Sjöstrand, Stefan Prestel, Stephen Mrenna, Richard Field (guest), Leif Lönnblad. On screen: Nadine Fischer. Also remotely connected: Peter Skands. Missing: Philip Ilten, Christine Rasmussen.

Cake celebration in Lund on 26 March 2019, on the occasion of the Pythia 6.4 article having reached 10,000 citations in the Inspire database.

Champagne celebration on the same theme, at Peter Skands' house outside Melbourne, on 10 April 2019.

Left to right: Peter Skands, Torbjörn Sjöstrand, Stephen Mrenna.

Left to right: Helen Brooks, Torbjörn Sjöstrand, Stephen Mrenna, Christian Bierlich, Ilkka Helenius, Peter Skands, Leif Lönnblad, Stefan Prestel, Philip Ilten, Nishita Desai, Rob Verheyen, Christian Preuss.

Participants in the first Pythia week, 8-12 April 2019, Monash University, Melbourne.

Front row: Ilkka Helenius, Peter Skands, Torbjörn Sjöstrand, Leif Lönnblad, Christian Preuss, Cody Duncan. Back row: Philip Ilten, Helen Brooks, Nishita Desai, Stefan Prestel, Christian Bierlich, Stephen Mrenna, Rob Verheyen.

Meeting in Oxford, 2024.

Left to right: Phil Ilten, Torbjörn Sjöstrand, Naomi Cooke, Javira Altmann, Christian Bierlich, Ilkka Helenius, Leif Lönnblad, Steve Mrenna.

Meeting in Lund, 2025.

Left to right: (back row) Christian Bierlich, Leif Lönnblad, Torbjörn Sjöstrand; (middle row) Tony Menzo, Naomi Cooke, Manuel Szewc, Phil Ilten; (front row) Christian Preuss, Ilkka Helenius, Riley Henderson Joni Laulainen, Stephen Mrenna, Lise Auffret.