//------------------------------------------------------------------------------//
EvtGen is a particle decay simulator specifically designed for the needs of
- B-physics studies. Complete manual of EvtGen is available at address:
- http://robbep.home.cern.ch/robbep/EvtGen/GuideEvtGen.pdf
+ B-physics studies. Complete manual of EvtGen is available at:
+ http://robbep.home.cern.ch/robbep/EvtGen/GuideEvtGen.pdf. Further information
+ can be found on the EvtGen official web site http://evtgen.warwick.ac.uk/src/
+ The EvtGen release installed here is taken from
+ http://svnweb.cern.ch/guest/evtgen/tags/R01-03-00
//------------------------------------------------------------------------------//
-[14/12/2009]
+[28/05/2014]
1)This module contains:
- - EvtGen original code organized in three directories:
- EvtGenBase-EvtGenModels-EvtGen. EvtGenModels directory contains all models
- avilable in EvtGen to decay particles.
+ - EvtGen original code organized in four directories:
+ EvtGenBase-EvtGenModels-EvtGen-EvtGenExternal.
+ EvtGenModels directory contains all models avilable in EvtGen to decay
+ particles. EvtGenExternal contains the "interface" class with the external
+ packages
- The interface classes AliGenEvtGen and AliDecayerEvtGen for AliRoot users:
the methods to decay particles are in AliDecayerEvtGen which represents
the implementation of AliDecayer using EvtGen package
- 2)EvtGen required libphotos.so to generate Final State Radiation. Photos code is
- located in PHOTOS directory.
+ 2)The external packages, interfaced with EvtGen by EvtGenExternal class,
+ are used to generate specific particle decays and
+ are located in the TEvtGen subdirectories (except for Pythia8):
- 3)The implemented cases to force beauty hadrons interest those channels:
- B->J/psi+X - B->J/psi+X,J/psi->e-e+ - B->J/psi+X,J/psi->mu-mu+ - B->e+X.
- Those are decayed by exclusive models of EvtGen, and all parameters and
- models used to decay them are not modified with respect to the official
- EvtGen release. Some of particles produced in the decay chain (i.e. Lamda_c
- from Lambda_b, Xi_c0 from Xi_b-, etc...) are decayed by Pythia with the
- configuration setting in the AliDecayerPythia.
+ - HepMC (http://lcgapp.cern.ch/project/simu/HepMC/download/HepMC-2.06.08.tar.gz)
+ The HepMC package is an object oriented event record written in C++ for High Energy
+ Physics Monte Carlo Generators.
+
+ - Tauola (http://tauolapp.web.cern.ch/tauolapp/resources/TAUOLA.1.1.4/TAUOLA.1.1.4.tar.gz)
+ C++ interface of Tauola code, specifically designed to generate tau decays.
+
+ - Photos (http://photospp.web.cern.ch/photospp/resources/PHOTOS.3.54/PHOTOS.3.54.tar.gz)
+ C++ interface of Photos code, specifically designed to generate Final State Radiation.
+
+ - Pythia8 (available in $ALICE_ROOT/PYTHIA8/)
+
+
+ 3)The "default" decay table with all particles and all decay channels
+ can be found in TEvtGen/EvtGen/DECAY.DEC. The definition of all
+ particles is done in the table "evt.pdl". Both tables (DECAY.DEC and evt.pdl)
+ are loaded during the initialization of EvtGen. Several decay tables are available
+ in the directory TEvtGen/EvtGen/DecayTable and are used to generate "forced" decay modes.
+ All parameters, models and BR used in these tables are not modified with respect
+ to the official EvtGen release.
+ The following decay tables are tested: BTOD.DEC, BTOELE.DEC, BTOJPSI.DEC, BTOJPSITOELE.DEC,
+ BTOJPSITOMU.DEC.
4)Polarization is still to be implemented in the interface classes.
- It would be done soon.
- 5)To use EvtGen to decay beauty particles adjust those lines in the Config.C:
+ 5)Below an example of the usage of EvtGen in AliRoot to decay beauty particles.
+ The following lines should be added in the Config.C:
+ // set the xmldoc path using PYTHIA8DATA enviroement var
+ gSystem->Setenv("PYTHIA8DATA", gSystem->ExpandPathName("$ALICE_ROOT/PYTHIA8/pythia8175/xmldoc"));
- //----- load libraries (after loading libpythia6.so)
- gSystem->Load("libphotos.so");
- gSystem->Load("libEvtGenBase");
- gSystem->Load("libEvtGenModels");
+ //----- load libraries
+ gSystem->Load("libHepMC");
+ gSystem->Load("libTauola");
+ gSystem->Load("libpythia8");
+ gSystem->Load("libPhotos");
gSystem->Load("libEvtGen");
+ gSystem->Load("libEvtGenExternal");
gSystem->Load("libTEvtGen");
//----- declare an AliGenCocktail