D0 global tracking user's guide: Generating data
D. Adams
08jun01 1550
Framework packages
The D0 framework passes control to a sequence of packages. Event
pacakges are called for each event. The sequence and the parameters
controlling these package are read in at run time from RCP files.
Here we describe the event packages included in the global tracking
system.
D0 software is physically organized into units which are also called
packages. These are not the same as framework packages.
Executables
D0 framework executables are constructed with selected framework
packages. Any executable containing the appropriate package may
be used to run that package. The global tracking system defines an
executable gtr which contains all the global tracking framework packages.
It is defined in software package
gtr_sys.
This wrapper provides an iterface to gtr which enables users to
easily mix and match many common packages. It can be used to run the
program on machines without the D0 run 2 software (e.g. the farms).
This directory provides some example run directories which show how
to use gtr_run for some common tasks.
Finding tracks
Tracks are found using the framework package GtrFindPkg which is
defined in the software package
gtr_find.
The input for track finding
is cluster chunks from one or more subdetectors. The output is a
a global track chunk.
The OBS files needed for default reconstruction
may be copied into the current directory with the command
gtr_find_get_obs. If d0setwa is run first, the user's private release
area will be searched before the public release area. If a directory
is provided on the command line, it will be searched before either of
these.
Finding tracks with Monte Carlo information
Tracks may also be "found" by using Monte Carlo information to find the
the clusters which belong together, i.e. those that come from the
same Monte Carlo track. The framework package which does this is
GtrMcFind and it is defined in package
gtr_mcfind.
Fitting tracks
Once tracks have been found, they may be refit using framework package
GtrRefitPkg defined in
gtr_refit.
Building Monte Carlo tracks from GEANT data
The framework package GtrMcTrackPkg is described in
gtr_mcsim.
It uses data from GEANT to build up a Monte Carlo track chunk.
Internal simulation
Global tracking provides a package GtrMcFillPkg which generates
its own Monte Carlo tracks. This internal simulation simply propagates
tracks to detector surfaces. It provides the option of adding multiple
scattering but no other interactions are included. This package is
defined in
gtr_mcfill.
There is no input chunk. The output is a Monte Carlo track chunk.
Track ntuple
The package GtrTuplePkg uses the global and Monte Carlo track chunks
to fill the global track ntuple which is described below. It is
defined in
gtr_tuple.
dladams@fnal.gov