Sherpa 2.2.9

Version 2.2.9 contains bug fixes and a few new features, and we encourage all users to update to this version.

If you spot any problem, please send us an email. If you would like to be informed about newer releases, please subscribe to our announcement mailing list.


The Sherpa package can be downloaded here: SHERPA-MC-2.2.9.tar.gz

In can also be accessed via git in the web interface:

  • v2.2.9 as tag matching the release tarball
  • rel-2-2-9 as branch including potential further patches

or cloned into a local working copy:

  • git clone -b rel-2-2-9

A Manual can be found online and in the Manual/ directory of the source. It is available in the HTML and INFO format and provides extensive documentation of all parameters.



  • Multiplicative approximate EW corrections !262
  • New shower evolution/scale schemes for better b-fragmentation modelling !278
  • Add additional EW_SCHEME options for DY with sin2ThetaW input !274
  • Improve UFO structure for SMEFT () and allow to use form factors in UFO !290 !291
  • added option to limit couplings at amplitude level in comix

Runtime issues

  • Respect polarisation of taus produced in hard decays (e.g. t -> b W (-> tau nu)) !296
  • Enable/Fix scale variations for loop generators that do not provide pole coefficients !259
  • Allow tau decays despite WIDTH[15]=0 !280

Compilation issues

  • Remove usage of auto keyword to avoid C++11 requirement !279
  • Compile heavy-flavour-fusing hooks by default !228
  • Update Rivet_Interface to deal with Rivet3 and HepMC3 !254
  • Use -fcx-fortran-rules compiler flag by default !304

Known issues

  • Dijet production with additional jets merged with the CKKW algorithm is broken in the 2.2.x series (#46)
  • Also see our issue tracker


The main reference for Sherpa 2.2.x is arXiv:1905.09127. Please cite this publication if you have used Sherpa 2.2.x for your studies. Additionally, each run will produce a file called Sherpa_References.tex which contains information about the modules used in this run and the corresponding publications which should be referred. If in doubt, please seek the advice of the Sherpa authors.


You can find a large collection of example setups for using SHERPA in various different colliders/processes in the Examples/ directory of the tarball. They are also described in the manual.