LHAPDF6: parton density access in the LHC precision era

Dec 23, 2014
21 pages
Published in:
  • Eur.Phys.J.C 75 (2015) 132
  • Published: Mar 20, 2015
e-Print:
Report number:
  • GLAS-PPE-2014-05,
  • MCNET-14-29,
  • IPPP-14-111,
  • DCPT-14-222
Experiments:

Citations per year

20142017202020232025050100150200
Abstract: (Springer)
The Fortran LHAPDF library has been a long-term workhorse in particle physics, providing standardised access to parton density functions for experimental and phenomenological purposes alike, following on from the venerable PDFLIB package. During Run 1 of the LHC, however, several fundamental limitations in LHAPDF’s design have became deeply problematic, restricting the usability of the library for important physics-study procedures and providing dangerous avenues by which to silently obtain incorrect results. In this paper we present the LHAPDF 6 library, a ground-up re-engineering of the PDFLIB/LHAPDF paradigm for PDF access which removes all limits on use of concurrent PDF sets, massively reduces static memory requirements, offers improved CPU performance, and fixes fundamental bugs in multi-set access to PDF metadata. The new design, restricted for now to interpolated PDFs, uses centralised numerical routines and a powerful cascading metadata system to decouple software releases from provision of new PDF data and allow completely general parton content. More than 200 PDF sets have been migrated from LHAPDF 5 to the new universal data format, via a stringent quality control procedure. LHAPDF 6 is supported by many Monte Carlo generators and other physics programs, in some cases via a full set of compatibility routines, and is recommended for the demanding PDF access needs of LHC Run 2 and beyond.
Note:
  • 21 pages, 4 figures, 3 tables. v2 updates eq. 22 (from arXiv:1205.4024) to correctly reproduce correlations
  • parton: density
  • parton: distribution function
  • numerical calculations: Monte Carlo
  • programming
  • CERN LHC Coll