LHE2ROOT Helpers

This contains lhe2root, a script for converting lhe files to root files using JHUGenMELA that is focused on 4l Higgs decays.

Installation Location

This package should be installed within an instance of JHUGenMELA. The recommended location, which would require no edits, would be the same directory as, or a directory below, mela.py and pythonmelautils.py within the main HexUtils repo. These are normally under HexUtils/AnalysisTools/JHUGenMELA/MELA/python. However, as long as LD_LIBRARY_PATH is set, which can be checked using the check_for_MELA function, python should be able to find MELA's location.

Programs Within This Package

• convert_all_to_ROOT.py

  • This program will take in command line arguments and convert all the files within your working directory, as well as any subdirectories below, to a ROOT file using lhe2root.py

• plot_one_quantity.py

  • This program will take in command line arguments and plot a single attribute from a list of ROOT files given

• plot_interference.py

  • Given a series of ROOT file interference triplets (one mixed sample file and 2 pure sample files i.e. AB, A, and B) as command line arguments, this program will plot their interference and compare the interference terms for each triplet against each other

• lhe_reader.py

  • Given a series of LHE files as command line arguments and an integer number of events this program will cut all of the files given down to the number of events requested

Useful Functions

All of the programs simply use the functions stored within lhe2root_methods.py or lhe_reader.py by taking in command line arguments. Should you desire to use any of these functions individually, that is very easy. Simply import lhe2root_methods or lhe_reader and continue.

The following functions are included in lhe2root_methods.py:

scale(counts, scaleto)
get_cross_section_from_LHE_file(LHE_file_path)
check_for_MELA()
recursively_convert(current_directory, argument, clean=False, verbose=False, exceptions=set(), write="")
plot_one_quantity(filenames, attribute, xrange, nbins=100, labels=[], norm=False, title="")
plot_interference(mixed_file, pure1, pure2, pure1Name, pure2Name, attribute, cross_sections, nbins=100, title="")

These functions have associated docstrings available to look at.

The following functions are included in the lhe_reader class in lhe_reader.py:

lhe_reader.cross_section()
lhe_reader.all_events()
lhe_reader.non_event_portions()
lhe_reader.cut_down_to_size(n, verbose=False)
lhe_reader.to_ROOT(argument, env, output_directory='./', output_prefix='LHE', verbose=False, replace=False)

The lhe_reader class also has associated documentation, visible either in the class or on the documentation site.

Useful Defined Constants

There are also some useful defined constants within uesful_funcs_and_constants.py. There are currently 3 of these such constants:

• lhe_2_root_options
  • This is a list of all the possible options that are available to lhe2root.py
• lhe_2_root_args
  • This is a list of all the possible other arguments that are not mutually exclusive in lhe2root.py
• beautified_title
  • This dictionary provides a conversion between the shorthand for an attribute (i.e. M4L) and the beautified version suitable for matplotlib (i.e. $m_{4\mu}$) You should edit this dictionary if you want to change the depiction of certain parameters!
• ranges
  • This dictionary does the same as beautified_title, except it converts the shorthand to the commonly defined ranges (i.e. phi $\in [-\pi, \pi ]$). You should edit this dictionary if you want to change the ranges of certain parameters!
• event_selection_regex
  • This is the regex that selects events in an LHE file

The following functions are also in the file:

• print_msg_box(msg, indent=1, width=None, title=None)
  safely_run_process(running_str, env={})
  check_for_MELA(env)

Dependencies

Dependencies Requiring Installation

You will need following packages. Some packages have dependencies (which are not listed). I would recommend using conda to do any package installations, as it will automatically download any secondary dependencies you may need. For packages that require a conda installation, the conda webpage for each package required is linked below:

• numpy
• matplotlib
• pandas
• ROOT
• uproot
• mplhep

Dependencies That Come Default with Python

Some of the packages are also packages that come with a default installation of Python. These packages, alongside their documentation, are listed below:

• os
• re
• argparse
• subprocess