eSTARlight

eSTARlight is a Monte Carlo that simulates coherent vector meson photo- and electro-production in electron-ion collisions. It can produce a variety of final states at different center of mass energies for different collision systems at arbitrary values for the photon virtuality.

Papers and presentations

• Exclusive vector meson production at an electron-ion collider: M. Lomnitz & S. Klein, Submitted to Phys. Rev. C and currently under review arXiv:1803.06420
• Coherent vector meson production at an EIC: M. Lomnitz and S. Klein, Presented at the Workshop for Deep Inelastic Scattering, Kobe Japan, 2018.

Authors

• Michael Lomnitz¹
• Spencer Klein¹

¹: Lawrence Berkeley National Laboratory, Relativistic Nuclear Collisions Program, Nuclear Science Division.

All rights rights reserved.

Declaration

Portions of this package were originally inherited/based on the STARlight Monte Carlo generator. We would like to aknowledge the authors J. Nystrand, J. Seger and Y. Gorbunov for their contributions to STARlight. This work was funded by the U.S. Department of Energy under contract number DE-AC-76SF00098.

Instructions for use

The following instructions illustrate the procedure to install and run eSTARlight in a *nix based environment:

• Download the code package from Hepforge or Github and move to the desired location, i.e. ~/the_path/eSTARlight
• Change to the installation directory of your choice
  • mkdir ~/my/installation/dir
  • cd ~/my/installation/dir
• Set up the installation using cmake:
  • cmake ~/the_path/eSTARlight/trunk
• Compile the code using (g)make:
  • (g)make
  • The compilation will produce two executables to run either STARlight or eSTARlight
• Set up the desired running conditions in the input file:
  • cp ~/the_path/eSTARlight/slight.in .
  • vim slight.in
  • Note: As of yet, the positron/electron beam must be set to beam1, it is selected by setting:
    • BEAM_1_Z = +/- 1 (as of yet both positrons and electrons are modelled identically)
    • BEAM_1_A = 0
• Run the simulation:
  • ./e_starlight > output.txt
  • output.txt will contain the program log and calculated cross-section for the simulation sample
  • The event catalogue will be emptied into the file slight.out
• Interpret the result. We have provided a macro to convert the output into a ROOT TTree:
  • root -b -q -l ~/the_path/eSTARlight/trunk/utils/ConvertStarlightAsciiToTree.C
  • TTree is output to starlight.root
• Analyze your data:
  • We have included template analysis (~/the_path/eSTARlight/analysis/) code that reads slight.root and fill histograms. For more details please look at the README
  • cd ~/the_path/eSTARlight/analysis
  • sh e_run.sh ~/the_path/starlight.root

Documentation

A more detailed version of the README is included as part of the software package, located in:

• ~/the_path/eSTARlight/trunk/Readme.pdf
• ~/the_path/eSTARlight/trunk/Readme.docx

Finally, the full documentation with class description and dependencies is also available with the package download. To view the documentation:
- Open the file ~/the_path/eSTARlight/trunk/doxygen/html/index.html

We have also included a config file to generate a fresh version of the documentation (for instance in the case of any updates). To following steps can be used to generate the documentation:

• Download and install the doxygen
• Move into the source code trunk:
  • cd ~/the_path/eSTARlight/trunk/
• If necessary, delete previous documentation to avoid any conflicts:
  • rm ~/the_path/eSTARlight/trunk/doxygen/html/*
• Generate the documentation:
  • doxygen estarlightDoxyfile.conf
• The documentation should be generated and available in the previous location