[Pythia8-announce] Pythia 8.306 now available

[Peter Skands]

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Dear All,

PYTHIA 8.306 has been released today, and can be downloaded from

• http://pythia.org

Note that this is the first release to the new Pythia.org webpage.

This is an "unscheduled" bug fix update, prompted by a showstopper bug in Powheg matching code, but a few other minor fixes are included also. A brief summary is included below and in the Update History part of the HTML manual.

Wishing you an enjoyable experience with PYTHIA 8.306.

Sincerely yours,
The Pythia 8 Collaboration
(Christian Bierlich, Nishita Desai, Leif Gellersen, Ilkka Helenius, Philip Ilten, Leif Lönnblad, Stephen Mrenna, Stefan Prestel, Christian Preuss, Torbjörn Sjöstrand, Peter Skands, Marius Utheim, Rob Verheyen)

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Summary list of changes for 8.306.

• Fixed incorrect scale being set when applying the POWHEG veto (e.g., main31.cc). Note that the number of emissions is correct in 8.303, but is incorrect in 8.304 and 8.305. Thanks to Mikhail Kirsanov.
• Fixed repeated initialization causing an ever expanding physics pointer list in the main Pythia class.
• Fixed issue for HepMC output from Vincia, which would previously issue warnings about inconsistent mother/daughter relationships, caused by Vincia's antenna-style bookkeeping by which emitted partons have two mothers instead of one. Minor modifications to Vincia's QCD shower to ensure that the first mother is the one that changed colour and hence would be identified with the "radiator" in a collinear context. Analogous modifications for QED so the most collinear parent is the first mother.
• Removed assert statements from Angantyr.
• Shortened Pythia constructor header.

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