parton – a Python package for parton distributions and parton luminosities

parton is a Python package providing parton distribution functions and parton luminosities. It uses the PDF data files provided by the LHAPDF project. Its API is partially compatible to LHAPDF's Python API, even though only a subset of its features are implemented.

parton is written in pure Python, i.e. it runs on Linux, Mac OS, and Windows.

Installation

To install the package without administrator privileges, run

python3 -m pip install parton --user

Command-line interface

parton provides a command-line interface that mimicks (and is partially compatible to) LHAPDF's lhapdf command. In particular, it can be used to install PDF grid files. It is accessed by running the package as a script,

python3 -m parton

For instance, to install a specific PDF set, run

python3 -m parton update
python3 -m parton install 'CT10'

If you already have a directory with PDF sets (e.g. from LHAPDF), that can be used as well.

Python usage

The API for numerically evaluating PDFs is modeled after LHAPDF's Python API:

from parton import mkPDF
pdf = mkPDF('CT10', 0)
# up quark PDF at x=0.1, Q=1000 GeV
pdf.xfxQ(2, 0.1, 1000)

If the PDF sets are in a non-default location (on Linux, the default location is ~/.local/share/parton/), this directory can be changed through mkPDF's pdfdir argument.

Parton luminosities are accessed similarly through the PLumi class, but the factorization scale has to be fixed on instantiation,

from parton import PLumi
# pdf has been defined above
plumi = PLumi(pdf, Q2=1000)
# u-ubar parton luminosity at shat/s=0.1
plumi.L(2, -2, 0.1)

License

parton is released under the MIT license.

Contributors

parton was originally written by David M. Straub (@DavidMStraub)

Other contributors:

• Peter Stangl (@peterstangl)

Citation info

parton cannot be cited at present. Please do not forget to also acknowledge the LHAPDF project.