Gabriele Cosmo
87 lines
3.3 KiB
Plaintext
87 lines
3.3 KiB
Plaintext
$Id: README 106393 2017-10-09 09:46:03Z gcosmo $
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------------------------------------------------------------
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Example of the external decayer implementation with PYTHIA6
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-----------------------------------------------------------
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The complete PYTHIA6 documentation can be found at:
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http://home.thep.lu.se/~torbjorn/pythiaaux/recent.html
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The PYTHIA6 external decayer was originally developed within
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the AliRoot framework, by Andreas Morsch (CERN).
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The dependence on the ALICE software was taken off
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by Christian Holm Christensen,
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The dependence on the Root framework and the integration in
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the Geant4 framework was done by Ivana Hrivnacova (IPN Orsay).
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The use of the external decayer is demonstrated with using the
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classes from common examples repository, see below their complete list.
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The G4Pythia6Decayer class provides the implementation of the
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G4VExternalDecayer interface with using PYTHIA6. In order
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to be able to use PYTHIA6, which is written in FORTRAN,
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a C++ interface class Pythia6 is provided. This class
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interfaces only the PYTHIA6 functions relevant to decay.
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The G4Pythia6Decayer is instantiated in the P6DExtDecayerPhysics builder,
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in the ConstructProcess() function where the external decayer is set
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to G4Decay process for all particles.
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To demonstrate the decay with external decayer,
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the B- meson is defined in ExG4PrimaryGeneratorAction01,
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as it has no own decay table defined within Geant4.
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With PYTHIA6, it is possible to force a selected decay
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type. This selection can be chosen interactively via
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the implemented Geant4 UI command:
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/pythia6Decayer/forceDecayType decayType
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where the available decay types are listed in the EDecayType
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enumaration.
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The classes Pythia6, G4Pythia6Decayer, G4Pythia6DecayerMessenger
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are independent from the example classes and can be reused
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in another user application.
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Installation:
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1. Download the PYTHIA6 source file from the PYTHIA6 download site:
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http://www.hepforge.org/downloads/pythia6
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2A.) With CMake: Build pythia6 library
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For a convenience a CMake file for building Pythia6 library from
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the source is provided in
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examples/extended/eventgenerator/CMakeLists.txt.pythia6.
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Build the pythia6 library following the instructions in this file
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and then define the environment variables:
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PYTHIA6 the path where pythia6 library is installed
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PYTHIA6_VERSION the pythia version
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2B.) With GNUmake: Define the environment variables:
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PYTHIA6 the path to pythia-versionX.f source code
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PYTHIA6_VERSION the pythia version
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e.g. If you download pythia-6.4.26.f.gz and unzip it in $HOME,
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then you have to set:
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export PYTHIA6=$HOME
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export PYTHIA6_VERSION="6.4.26"
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Pythia6 will be then compiled together with example code.
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3. Compilation:
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Then the example is compiled in a standard way, see examples/README_HowToRun.
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Note that with GNUmake build, an additional step 'gmake setup' is
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needed before 'gmake'.
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Execution:
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% pythia6_decayer pythia6_decayer.in
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This example uses the following user action classes from the extended examples common
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repository available in common subdirectory:
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DetectorConstruction
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GunPrimaryGeneratorAction
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