Code to analyze (SoftDrop recursive) Splitting

This code utilizies the JETSCAPE/X-SCAPE parton shower graph implementation (stand alone) to represent the ouput of a recursive SoftDrop de-clustering algorithm on simulated (p+p) data. The current implementations provides a (stand alone) reader setup to study the JETSCAPE p+p tune (jetscape_user_PP19.xml) either in the JETSCAPE Ascii or gzipped Ascii format. To prodcue the data it is highly encouraged to utilzie the JETSCAPE/X-SCAPE docker setup (providing an out of the box conatiner to run JETSCAPE 3.6 and X-SCAPE 1.1) to prodcue the data. An interface to Pythia8 including the parton graph in the same graph format is under development.

Required packages

The JETSCAPE parton shower graph and reader are implemnted stand-alone and do not require a JETSCAPE/-XSCAPE local installation.

• FastJet > 3.0 and FastJet contrib including the recursive softdrop algorithm are required and are expected to be installed in the same directory. The current cmake uses the fastjet-config program and expect it in the standard paths.
• ROOT > 6.20 (standard local installation) is utilized in the test program (anaTest) for further histogram etc output. However in principle one could omit ROOT.
• Graphviz is needed to visualize the parton shower graphs (currently creates a PDF output). Install on a Mac via homebrew: brew install graphviz (the easiest way) and on Linux use the distribution specific package manager.

Build and run/test

mkdir build
cd build
cmake ..
make

C++11 is the required standard. However if some off the libraries are compiled with C++17 (ROOT etc for example) use:

cmake -DCMAKE_CXX_STANDARD=17 ..

The example/test program anaTest should be visible in the build directory. Example data in gzipped JETSCAPE format are provided in the example_data directory.

./anaTest

You can provide the input specifically as the first argument and the root output as the second argument. By default the example data containing 20 p+p events (RHIC energies) is used.

If you have ROOT installed you should find a ROOT output containing some histograms. If you have graphviz installed and it is properly working, you should find PDF files containing the MC shower graph, the SD graph on parton and on hadron level.