The BkgTreePlotter package provides tools to visualise the MC true origin of a background candidate (which works as well for signal candidates). It has been presented https://indico.cern.ch/event/355690/contribution/3/material/slides/0.pdf

If included in the DaVinci main sequence, a .dot file will be created for every candidate at the input TES location(s). The MCTools/BkgTreePlotter package is required and the configuration is:

from Configurables import DotCreator
DaVinci().appendToMainSequence ( [ DotCreator(Inputs = [ "Phys/MyTau23MuCandidates/Particles" ] ) ] )

for an apropriate TES location. The .dot files can be converted to .pdf with the shell script in the package: ./postprocessing.sh will process all .dot files in the current working directory.

The output should look somehow like this:


Usage recommendation

I recommend not to create thousands of plots to look at them (dull work and often inconclusive). Either cut very tight on your BDT / neural network until you're left with O(10) events or create a short list of run&event numbers from your ntuple (I assume that you already have ntuples, so let's start from there) and then process these events:

from Configurables import LoKi__ODINFilter
odin = LoKi__ODINFilter (
    'ODINfilter' ,
    Code       =  ' odin_runevts (  the_list ) ' ,
    Preambulo = [
    "from LoKiHlt.functions  import *" ,
    "from LoKiHlt.decorators import *" ,
    "the_list = runevt_lst ( [RunEvt(112290, 888056458), RunEvt(112290,
891370819)] )" ])
DaVinci().EventPreFilters = [odin]


(enabled by default) suppresses string fragmentation, so you won't see gazillions of fragmentation particles. For tagging studies, you might want to change this.


Please send feedback to Paul.Seyfert-at-mib.infn.it. Especially the following items are of interest:

  • at the moment, each candidate receives their own diagram. (from the filename you will
    see that the candidates are from the same event)
    → feedback welcome: should they go to the same diagram? how to highlight which
    tracks belong to which candidate?
  • when you reconstruct B 0s → D s (KKπ)π, the plot wonít distinguish the bachelor pion from
    the D daughter pion.
    → feedback welcome: is this needed? suggestions how to best visualise
  • I didnít test how the code reacts when encountering a π 0 candidate and I know too little
    about MC association of neutral clusters
    → feedback welcome: test case
  • At the moment the list of MCVertexTypes which are ignored is hard coded. There is no
    cut on the z position of the MCVertex
    → feedback welcome: is this needed to be configurable?
-- PaulSeyfert - 2015-05-11
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PNGpng 2812047.36542.0.dot.png r1 manage 53.9 K 2015-05-11 - 16:06 PaulSeyfert an example (with a custom font)
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Topic revision: r2 - 2016-02-01 - PaulSeyfert
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