B-Tagged and non-B-Tagged Samples in the TopView Ntuple

It is possible to access three samples of jets, with respect to their B-Tagging status, in the TopView ntuple. The first sample is B-Tagged jets, the second is jets that are not B-Tagged jet, and the third is all jets (B-Tagged jets plus non-B-Tagged jet).

Accessing jets with and without B-tagging

The method in which the jets with and without B-tagging are accessed depends on the version of TopView.

Top View Version 11

Variables for B-Tagged jets are denoted by the prefix TJet_ and variables without a B-Tagged jet are denoted by the prefix PJet_. To obtain a sample of all jets, it is necessary to add TJet_ and and PJet_ variables.

Since the TJet_ and PJet_ objects are stored in separate arrays and are combined into a single array to form the B-Tagged + non-B-Tagged sample, it is necessary to order the combined array in pT. Failure to do so was causing the small peaks in η (see figure below) observed when the non-B-Tagged jets always occupied the first positions in the array and were therefore always considered to have the highest pT.

Top View Version 12

There is only a PJet_ prefix for variables and the tagging status is given by the flag PJet_BTagged. B-Tagged jets are denoted by PJet_ with PJet_BTagged=TRUE, jets that are not B-Tagged jets are denoted by PJet_ with BTagged=FALSE, and all jets are denoted simply by PJet_ without any requirement on PJet_BTagged.

Plots of Samples with and without B-tagged Jets for the s-channel

The plots show samples of B-Tagged jets (red lined histogram), non-B-Tagged jets (green lined histogram), and B-Tagged + non-B-Tagged jets (black solid histogram). The B-tagged sample extends only to η=2.5 because tracking restrictions at greater η.

The B-Tagged + non-B-Tagged sample on the left is not ordered in pT and the small peaks seen where η is slightly larger than 2.5 is a result of the non-B-Tagged jets being considered to have the highest pT because they were always placed in the leading positions of the jet array. In the plot on the left the jets in the B-Tagged + non-B-Tagged sample are ordered in pT and no peak is visiable.

jet_tagging_005501_eta1_one_new.png jet_tagging_ordered_005501_eta1_one.png

-- PatRyan - 20 Feb 2007

Topic attachments
I Attachment Action Size Date Who Comment
BJet.pngpng BJet.png manage 263.7 K 21 Feb 2007 - 10:06 UnknownUser  
Jet.pngpng Jet.png manage 313.6 K 21 Feb 2007 - 10:12 UnknownUser  
NonBJet.pngpng NonBJet.png manage 323.4 K 21 Feb 2007 - 10:12 UnknownUser  
jet_005501_eta1_p_and_t_one.pngpng jet_005501_eta1_p_and_t_one.png manage 20.7 K 21 Feb 2007 - 10:45 UnknownUser  
jet_005501_eta1_p_one.pngpng jet_005501_eta1_p_one.png manage 19.3 K 21 Feb 2007 - 10:45 UnknownUser  
jet_tagging_005501_eta1_one.pngpng jet_tagging_005501_eta1_one.png manage 21.1 K 22 Feb 2007 - 13:29 UnknownUser  
jet_tagging_005501_eta1_one_new.pngpng jet_tagging_005501_eta1_one_new.png manage 35.6 K 27 Feb 2007 - 13:54 UnknownUser  
jet_tagging_ordered_005501_eta1_one.pngpng jet_tagging_ordered_005501_eta1_one.png manage 32.2 K 02 Mar 2007 - 09:49 UnknownUser  
Topic revision: r21 - 16 Oct 2009, TomRockwell

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