The Trimmed Kalman vertex reconstructor
Complete:
Overview
The Trimmed Kalman vertex reconstructor iteratively uses the
Trimmed Kalman vertex fitter to find and fit interaction vertices. After each fitted vertex, the remaining tracks are re-used to search for further vertices.
The fitter is implemented in the package
RecoVertex/TrimmedKalmanVertexFinder
Usage
A default
An easy way to use the TKVF is through the KalmanTrimmedVertexFinder. It uses a conventional
Kalman filter to fit the vertices, without the user having to specify anything.
It is then used like any other VertexReconstructor.
KalmanTrimmedVertexFinder finder;
vector<TransientVertex> vertices = finder.vertices ( vector<TransientTrack> tracks );
Parameters
To change the parameters, the easiest is to use the
setParameters(ParameterSet)
method. Alternatively, individual set methods can be used. The PSet needed is the following:
GSFParameters = cms.PSet(
ptCut = cms.double(0.0),
vtxFitProbCut = cms.double(0.01),
trackCompatibilityToPVcut = cms.double(0.05),
trackCompatibilityToSVcut = cms.double(0.01),
maxNbOfVertices = cms.int32(0)
)
The parameters are the following:
Parameter Name |
Description |
Default |
method |
maxNbOfVertices |
the maximum number of vertices searched for. 0 means no limitations |
0 |
setMaxNbOfVertices(int) |
ptCut |
the minimum pT (in GeV) of the tracks used to make vertices. |
1.5 |
setPtCut(float) |
trackCompatibilityToPVcut |
the probability below which a track is considered incompatible with the 1st vertex candidate formed. |
0.05 |
setTrackCompatibilityCut(float) |
trackCompatibilityToSVcut |
the probability below which a track is considered incompatible with the next vertex candidates formed. |
0.01 |
setTrackCompatibilityToSV(float) |
vertexFitProbabilityCut |
the probability below which a vertex is rejected |
0.01 |
setVertexFitProbabilityCut(float) |
-- Main.speer - 05 Jul 2007