[Pythia8-announce] Pythia 8.244 now available

[Torbjörn Sjöstrand]

Dear All,

A new release PYTHIA 8.244 can now be downloaded from

       http://home.thep.lu.se/Pythia

There are only a very few changes, for bugs that have affected
some specific critical applications:

* The combination of weight variations, within the context of
   uncertainty bands, has not been well documented and therefore prone
   to misunderstandings. Now the behaviour of Info::getGroupWeight()
   has been made transparent, and the documentation in Variations has
   been improved. The main121.cc example has been modified accordingly.

* Restore the capability to set width and lifetime of a resonance
   separately (changed in 8.240). Now the lifetime is set from the
   width only if the allowCalc() method of the resonance class returns
   true.

* Updated handling of Powheg files, such that files with
   multiple/variable number of real emissions can be handled. The
   default value of the POWHEG:nFinal parameter has been changed to -1,
   see the POWHEG Merging documentation.

* Limit the amount by which transverse smearing of the space-time
   quark-antiquark string breakup vertices can give large shifts. This
   is regulated by the new HadronVertex:maxSmear parameter. Also some
   other related changes.

* Fixes for consistent storage of production vertices in units of mm.
   Thanks to Christopher Plumberg.

* Number of weights in info is reset to 1 for each new init call.

Wishing you an enjoyable holiday season.

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