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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

KalmanTrimmedVertexFinder finder; vector<TransientVertex> vertices = finder.vertices ( vector<TransientTrack> tracks );

To change the parameters, the easiest is to use the

method. Alternatively, individual set methods can be used. The PSet needed is the following:
**setParameters(ParameterSet)**

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 |
---|---|---|---|

vertexFitProbabilityCut | the probability below which a vertex is rejected | 0.01 | setVertexFitProbabilityCut(float) |

trackCompatibilityToSVcut | the probability below which a track is considered incompatible with the next vertex candidates formed. | 0.01 | setTrackCompatibilityToSV(float) |

trackCompatibilityToPVcut | the probability below which a track is considered incompatible with the 1st vertex candidate formed. | 0.05 | setTrackCompatibilityCut(float) |

ptCut | the minimum pT (in GeV) of the tracks used to make vertices. | 1.5 | setPtCut(float) |

maxNbOfVertices | the maximum number of vertices searched for. 0 means no limitations | 0 | setMaxNbOfVertices(int) |

-- Main.speer - 05 Jul 2007

This topic: CMSPublic > CMSCommunicationsGroup > CMSCommunicationsProjects > WebHome > SWGuide > SWGuideVertexReco > SWGuideOfflineSecondaryVertexFinding > SWGuideTrimmedKalmanVertexFinder

Topic revision: r2 - 2009-03-11 - ThomasSpeer

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