Global Tracking Base Classes (gtrbase)

Global Tracking Base Classes (package gtrbase)

28dec00 1300
Code version 0.21

An introduction to D0 global tracking may be found at http://www-d0.fnal.gov/global_tracking.

Links to code

The description below includes links to the code contained in this package. This version of the code may not be the most recent.

Description

GTR package gtrbase contains the base global tracking classes. Subdetector classes make use of these.

The physical components include:

GTrackState ( header, FitStatus header, source, test )
GTrack ( header, test header, source, test )
GTrackPropagator ( header, source, test )
McTrackState ( header, source, test )
McTrack ( header, source, test )
McParent ( header, source, test )
GtrTrfPropagator header, source, test )

The component dependencies are illustrated in the [nonexistent] physical dependency diagram.

This package depends on the following external packages:

d0cluster_evt - Generic clustering with EDM
d0cluster - Generic clustering
trffit - TRF++ fitting classes
trflayer - TRF++ layer classes
trfbase - TRF++ base classes
trfutil - TRF++ utilities
chunkptr - chunk pointer template
ptr - Pointer classes
edm - D0 event data model
identifiers - D0 event data model identifiers
d0om - D0 persistence

The classes defined in the above components are described below. Each class is defined in a component of the same name unless otherwise indicated. The descriptions are brief. See the header files for details.

Global track

GTrack is the class describing a global track. It consists of a list of GlobalTrackState objects. Each of those includes a track fit and optional cluster and miss pointers. collection of clusters. Clusters which are to be part of global tracks must meet the generic cluster interface.

GTrack includes a method to return the state at any existing surface.

Global track propagator

Class GTrackPropagator may be used to find the state of a GTrack at a new surface. It propagates the fit from neighboring surfaces.

Monte Carlo track

McTrack describes a Monte Carlo track as a list of one or more McTrackState objects. The latter specify a VTrack at different points along the track trajectory.

McTrack provides a method to return the state at any existing surface. It also allows the user to fetch the MC ID for the MC track which created the states of this McTrack. Condensed information about the track's MC ancestry can be obtained from the track's McParent.

Monte Carlo track Parentage

McParent provides a condensed summary of the MC Track's parentage. It does not contain the full chain of parents, but does store information about "interesting" ancestors. It provides methods allowing the user to ask whether the track had a particular parent type, but does not return specific information about that parent.

Parentage is stored in a bit pattern with the following meanings:

 1 = u, d or s quark or anti-quark
 2 = c quark
 3 = anti-c
 4 = b quark
 5 = anti-b
 6 = t quark
 7 = anti-t
 8 = Z0
 9 = W-
10 = W+
11 = psi
12 = upsilon
13 = tau-
14 = tau+

Propagator

GtrTrfPropagator provides access to a TRF++ propagator which can handle any combination of cylinder, z-plane, xy-plane and DCA surfaces.

Questions or comments to dladams@fnal.gov.