Plugin for the CRPropa simulation code to include the production of muon pairs from the interaction between gamma rays with background radiation fields.
The header of the EMMuonPairProduction class is defined in EMMuonPairProduction.h. The C++ file EMMuonPairProduction.cc contains the interaction class functions and the function to produce the secondaries. The file EMMuonPairProduction.i is the SWIG interface for python usage. This structure follows the usual CRPropa modules for electromagnetic processes, e.g. see CRPropa EMPairProduction.
The python script testPlugin.py tests the installation (see below) of the example plugin as presented here.
An updated version of the CRPropa3-data repository has been develped to include the interaction rates for this plugin, see EMCascadePlugins-data.
For the installation of the plugin you need a running CRPropa version (see installation documentation). This is done analogously to the installation of CRPropa. We recommend to activate the same virtual python environment that you use to run CRPropa.
First create a build folder within the plugin's directory and move there.
mkdir build && cd build/
Now you can run cmake to configure your project:
ccmake ..
At this step you have to set the installation path and the path to your swig interface of the current CRPropa installation (if it is not found by cmake).
After configuration (press c) and generation (press g) you can now build and install your plugin
make install
Now you can run the python test script.
python ../testPlugin.py
If you use this plugin in your work, please cite:
G. Di Marco, R. Alves Batista, M.A. Sánchez-Conde.
Gamma rays as leptonic portals to energetic neutrinos: a new Monte Carlo approach.
arXiv:2507.21867 [astro-ph.HE] (2025).
Available at: https://arxiv.org/abs/2507.21867