b Tag Analysis with bare ROOT in CMSSW 1.6

To quickly look at the b tag information inside a CMSSW dataset, it can be convenient to simply open the CMSSW dataset with bare ROOT. However, you will only be able to look at simple data members (e.g. float, int) inside classes, as illustrated below:

root rfio:///castor/cern.ch/cms/store/mc/2007/9/11/RelVal-RelValTTbar-1189470628/0000/22BEE924-7360-DC11-A1E0-001A92971B9C.root

(note the need to add "rfio:///castor/cern.ch/cms/" to dataset name provided by DBS, in order to open it interatively).

TBrowser b;

and then navigate in the TBrowser to the Event directory, where you can find the b tag JetTags. The name is of the form `C++ namespace' `class name'_label__Rec', as shown in the following screen capture:


Double-clicking on recoJetTags_jetProbabilityJetTags__Rec and then on recoJetTags_jetProbabilityJetTags__Rec.obj lets one see the C++ data members of the JetTag object, as shown in this screen capture:


Double-clicking on recoJetTags_jetProbabilityJetTags__Rec.obj.m_discriminator shows the histogram of the b `probability' tag discriminator value:


-- IanTomalin - 24 Oct 2007

Topic attachments
I Attachment History Action Size Date Who Comment
PNGpng 160_ROOT_prob_histo.png r1 manage 23.5 K 2007-10-24 - 10:38 IanTomalin  
PNGpng 160_TBrowser_Dump1.png r1 manage 120.8 K 2007-10-24 - 10:38 IanTomalin  
PNGpng 160_TBrowser_Dump2.png r1 manage 23.3 K 2007-10-24 - 10:38 IanTomalin  
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Topic revision: r4 - 2008-02-27 - AreshVedaee
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