Spythia Home Page

Last updated 07 Nov 2001.

Please see the new Pythia 6.2 release which includes the Spythia code.
This is the only supported version.

A new Pythia release with Supersymmetry updates has occurred!
This includes the addition of complex phases, polarization effects, upgraded Higgs sector, etc.

There is also code available for translating the output of Isasusy into the Pythia MSSM parameters.

  • A version that works with the latest version of Isasusy, thanks to Steve Muanza, is available here: new_pyfris.f .


    • Also, thanks to John Smith (CDF, UC Davis) and Mario Paolo Giordani for useful feedback.
    The code should be compiled and linked with the appropriate Isajet/Isasusy library.
    Feedback is, of course, always appreciated.

    Here is a listing of some bugs, fixes and general improvements. This is under construction.

  • 1 July 1999: I discovered today a bug in the pre-SUSY Pythia code. It appears that the CP-odd Higgs boson decays to fermion pairs has the wrong beta dependence. I am sending word to Torbjorn. Also, the Higgs boson decays to sparticles was inadvertently turned off in version 6.126 and later.
  • 2 May 2000: Color flow bug in PYSCAT which affected tau1-tau2 production at hadron colliders. Fixed in version 6.140 and higher.
  • 6 May 2000: There was a bug in h-A production where t-channel exchanges were being included.
  • 7 Nov 2001: The treatment of the tau sneutrino mass is not correct for the case when the stau is treated separately. The D-term is incorrectly calculated to be several GeV larger than it should be.

    Comments or problems to mrenna@physics.ucdavis.edu