xsec: the cross-section evaluation code

xsec is a tool for fast evaluation of cross-sections, taking advantage of the power and flexibility of Gaussian process regression.

For a detailed description of the methodology, validation and instructions for usage, see https://arxiv.org/abs/2006.16273.

Installation

Requirements

xsec is compatible with both Python 2.7 and 3. The following external Python libraries are required to run xsec:

• setuptools 20.7.0 or later
• numpy 1.16 or later
• scipy 1.0.0 or later
• joblib 0.12.2 or later
• dill 0.3.2 or later
• pyslha 3.2.3 or later

pip installation

xsec can be installed from PyPI using

pip install xsec

Optionally with the --user flag if your IT department is mean.

Alternatively, you can clone the repo from GitHub and install from there:

git clone https://github.com/jeriek/xsec.git
pip install ./xsec

It is also possible, though not recommended, to use the code without pip installation. In that case, to install only the requirements, run

pip install -r requirements.txt

Downloading required data

The pip installation does NOT automatically include the data required to run xsec. To download data after the pip installation, ensure that the pip install directory for scripts, e.g. ~/.local/bin, is in $PATH, and execute the following shell command:

xsec-download-gprocs [-g GP_DIR] [-t PROCESS_TYPE]

The first optional argument GP_DIR specifies the name of the (preferably new) directory where the data files will be downloaded and extracted. If this argument is not specified, a new directory gprocs is created in the current working directory. The second optional argument PROCESS_TYPE allows for selecting which data to download:

• gg (gluino pair production, 220 MB)
• sg (1st/2nd gen. squark--gluino pair production, 148 MB)
• ss (1st/2nd gen. squark pair production, 1.6 GB)
• sb (1st/2nd gen. squark--anti-squark pair production, 766 MB)
• tb (3rd gen. squark--anti-squark pair production, 210 MB)
• all (everything, 3 GB)

The default option is all.

(If you have not pip-installed xsec, the download script can be executed from the scripts folder.)

Testing the installation

To check whether the xsec installation works properly, download the gluino pair production data (gg) and try a test cross-section evaluation:

xsec-download-gprocs -t gg [-g GP_DIR]
xsec-test [-g GP_DIR]

If no argument is given to xsec-test, the data files are assumed to be in a subdirectory called gprocs in the current working directory, otherwise the user-specified path GP_DIR is used.

Removing the package

Uninstalling xsec is as simple as running

pip uninstall xsec

Code examples

An example main program showing how to use xsec can be found in the example_xsec_eval.py file. This shows evaluation both by specifying the model parameters by hand and by importing an SLHA file. An example showing a simple loop over parameters is available in example_xsec_loop.py.

Licence

xsec: the cross-section evaluation code

Copyright (C) 2020 Andy Buckley, Anders Kvellestad, Are Raklev, Pat Scott, Jon Vegard Sparre, Jeriek Van den Abeele, Ingrid A. Vazquez-Holm

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see https://www.gnu.org/licenses/.