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ntuple:ivf [2013/09/20 14:48] – created clange | ntuple:ivf [2013/10/23 16:38] – [Steps for MSSM Hbb analysis] clange | ||
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====== Inclusive Vertex Finder (IVF) ====== | ====== Inclusive Vertex Finder (IVF) ====== | ||
- | need to check out two additional | + | The IVF will run out-of-the-box in CMSSW_5_3_11. If unsure, you can check out the following |
- | '' | + | |
+ | cvs co -r V01-10-02 RecoBTag/SecondaryVertex | ||
- | '' | + | To use the same approach as the VHbb group, one also needs to check out two additional packages: |
- | '' | + | cvs co -d IVF/ |
+ | cvs co -d ZSV/ | ||
+ | | ||
Last command needed to update really old IVF package config files to BuildFile.xml files. | Last command needed to update really old IVF package config files to BuildFile.xml files. | ||
- | === Useful links === | + | ===== Work flow ===== |
- | partly used in VHbb ntuples: | + | |
- | *https:// | + | ==== General vertexing ==== |
+ | |||
+ | In order to get the IVF to work one has to perform inclusive vertexing by including [[https:// | ||
+ | |||
+ | process.load(' | ||
+ | |||
+ | The IVF runs on pre-selected vertices. After a coarse pre-clustering based on track distances and angles, vertices are reconstructed with the Adaptive fitter (outlier resistant, iterative procedure). This is done using the inclusive vertex finder from the [[https:// | ||
+ | |||
+ | * Source code: [[https:// | ||
+ | * Configuration file: [[https:// | ||
+ | |||
+ | These vertices are then merged depending on their significance in distance and the fraction of tracks they share (in particular vertices with a large fraction of common tracks are merged): | ||
+ | |||
+ | * Source code: [[https:// | ||
+ | * Configuration file: [[https:// | ||
+ | * using the standard config: | ||
+ | * maxFraction = 0.7 | ||
+ | * minSignificance = 2 | ||
+ | |||
+ | In the next step it is made sure that all tracks belong either to a secondary vertex or the primary vertex only optimising the assignment of tracks to vertices, followed by another vertex fit: | ||
+ | |||
+ | * [[https:// | ||
+ | * [[https:// | ||
+ | |||
+ | These refitted vertices are then again merged depending on their significance in distance and the fraction of tracks they share: | ||
+ | |||
+ | * Source code: [[https:// | ||
+ | * Configuration file: [[https:// | ||
+ | * config is overwritten by [[https:// | ||
+ | * maxFraction = 0.2 | ||
+ | * minSignificance = 10 | ||
+ | |||
+ | ==== b-vertex filtering ==== | ||
+ | |||
+ | The optimised vertices undergo a b-vertex filter: | ||
+ | |||
+ | * Source code: [[https:// | ||
+ | * Configuration file: [[https:// | ||
+ | |||
+ | ==== b to charm decay vertex merging ==== | ||
+ | |||
+ | The b-to-charm decay vertex merging attempts to identify B to D meson decays and merges them based on DeltaR, the vertex mass, the angle between them and the relative transverse momentum: | ||
+ | |||
+ | * Source code: [[https:// | ||
+ | * Configuration file: [[https:// | ||
+ | |||
+ | ===== Useful links ===== | ||
+ | partly used in VHbb ntuples: | ||
+ | * VHbb recipe: | ||
* http:// | * http:// | ||
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twiki documentation: | twiki documentation: | ||
- | * https:// | ||
* official recipe: https:// | * official recipe: https:// | ||
+ | * combination with CSV tagger: https:// | ||
CMSSW: | CMSSW: | ||
- | * http://cmssw.cvs.cern.ch/cgi-bin/cmssw.cgi/CMSSW/ | + | * https://github.com/cms-sw/cmssw/ |
+ | * https:// | ||
+ | ===== Current errors ===== | ||
+ | |||
+ | none | ||
+ | |||
+ | |||
+ | ===== Steps for MSSM Hbb analysis === | ||
+ | |||
+ | cvs co -r V02-02-06 | ||
+ | cvs co -r V01-10-02 RecoBTag/SecondaryVertex | ||
+ | |||
+ | In the python steering file: | ||
+ | |||
+ | ## IVF inclusive vertexing | ||
+ | process.load(' | ||
+ | # | ||
+ | # | ||
+ | process.load(' | ||
+ | |||
+ | process.IVFpreProcessing = cms.Sequence(process.inclusiveVertexing * process.inclusiveMergedVerticesFiltered * process.bToCharmDecayVertexMerged) | ||
+ | process.IVFpostProcessing = cms.Sequence(process.btagging * process.inclusiveSecondaryVertexFinderTagInfosFiltered * process.simpleInclusiveSecondaryVertexHighEffBJetTags * process.simpleInclusiveSecondaryVertexHighPurBJetTags * process.doubleSecondaryVertexHighEffBJetTags) | ||
+ | |||
+ | Not sure whether one should also explicitely add: | ||
+ | |||
+ | process.ak5JetTracksAssociatorAtVertex * | ||
+ | |||
+ | before b-tagging since the track-jet association is mentioned in the recipe. | ||
+ | |||
+ | Check: | ||
+ | RecoBTag/ | ||
+ | RecoBTag/ | ||
+ |