ISAWIG

ISAWIG is a package of subroutines designed to work with the ISAJET SUGRA and general MSSM programs to produce a data file containing the masses, lifetimes and branching ratios of the SUSY particles which can be read in by the HERWIG event generator.

The first official version 1.1 was released on the 14th of December 1999, with the release of HERWIG 6.1. The current version is now version 1.2 of 15th October 2002 which coincides with the release of HERWIG 6.5.

The ISAWIG program

The ISAWIG program in addition to converting the output from ISAJET into a form HERWIG can read in, includes the following additional features.

The option of violating R-parity, including the case when more than one of the R-parity violating couplings is non-zero.
The calculation of all two body R-parity violating squark and slepton decay modes, including left/right stop, sbottom and stau mixing.
The calculation of the three body R-parity violating gaugino and gluino decay modes, again including the left/right stop, sbottom and stau mixing.
A interface to HDECAY to calculate next-to-leading order Higgs decay rates and branching ratios.

The program and the structure of the data file are described in more detail in the HERWIG manual.

To produce a data file you will need the following

A copy of the ISAJET code. At the moment ISAWIG is designed to run with version 7.64 of ISAJET which can be obtained from the ISAJET web page.
A modified version of either the ISAJET SUGRA or general MSSM programs which are available here
- The SUGRA program SUGRUN
- The MSSM program SSRUN
The main ISAWIG code.
You will also need to make some changes to interface with HDECAY which are described here

Our conventions and the conversions are given here.

NEW! To coincide with the release of HERWIG 6.5 we have released a new version of the code. As there has also been a new release of HDECAY, and several releases of ISAJET we are now using C preprocessing in order to allow the user to specify the version of these packages they are using at compile time. In order to simplify this the code for the HDECAY interface has been merged into the main ISAWIG code. The default is that the code will run with ISAJET7.64 and without using HDECAY. In order to use either ISAJET7.63 or ISAJET7.58 the following compiler flags should be used

-DISAJET758 for ISAJET7.58
-DISAJET763 for ISAJET7.63

when compiling the ISAWIG, SUGRUN and SSRUN code. It is particularly important that this is done when running with ISAJET7.58 as several common blocks changed size between ISAJET7.58 and ISAJET7.63. If you wish to use the HDECAY interface you should use the following option when compiling the ISAWIG code

-DHDECAY2 for HDECAY2.0
-DHDECAY3 for HDECAY3.0

It should be noted that the interface to the new version of HDECAY allows many of the HDECAY parameters which were previously hard-wired to be set by the user. The old version of ISAWIG can be found here.

A complete list of the changes since the first official version is kept here.

Input Files

There are now a lot more SUSY benchmark points on the market here are input files for some of them.

LHC SUGRA and GMSB points.
Snowmass SUGRA, GMSB and AMSB points.

N.B. while the LHC points were generated using ISAJET7.64 the Snowmass points were generated using ISAJET7.58 as defined in the Snowmass standard.

Alternative files which use HDECAY for the calculation of the Higgs decay rates can be found here.

You can also create an input file by hand. In which case the file must follow the format given in the HERWIG documentation, as described here

Peter Richardson

Last modified: Mon Oct 21 15:01:32 BST 2002