It may be useful to print the decay tree of a Monte Carlo particle that was associated to a reconstructed particle. Suppose you have a preselection and you want to see what particles the background, that passes your preselection, consists of. As your reconstruction “thinks”, your reconstructed particles are all signal, you have to print the decay tree of the Monte Carlo particle associated to your reconstructed particle. The following components save the decay-string of a Monte Carlo particle in a txt-file (in DaVinci) and convert them into a LaTeX-table.

There are 3 components:

• A DaVinci algorithm (Bthat writes the decay string in a text-file.
• A standalone C++ class, that puts the decay-string in a formatted LaTeX-table.
• A standalone C++ class, that converts the Monte Carlo particle numbers in a LaTeX-string with the particle name.

This algorithm takes your reconstruced mother particle from CombineParticles, assigns the respective Monte Carlo particle and prints all daughters (with their respective daughters if they are not stable, etc. ) in ascending order, with antiparticles coming after particles. The decay strings are stored in a file name BG_cat.txt. In your options-file, add:

from Configurables import BGCat

BGCategory = BGCat("BGCategory")
BGCategory.addTool( PhysDesktop() )
BGCategory.PhysDesktop.InputLocations = ["Phys/yourLocation"]
BGCategory.OutputLevel = 4

yourSequence.Members.append(BGCategory)

yourLocation may be something like Bsmumu, when you are doing Bsmumu = CombineParticles(“Bsmumu”). In your /src directory, add: BGcat.cpp and BGcat.h, which are located at: /afs/cern.ch/user/d/decianm/cmtuser/DaVinci_v21r0/Phys/DaVinci/src/code (cut the .source-ending off)