MEKS: A program for computation of inclusive jet cross sections at hadron colliders

Abstract

EKS is a numerical program that predicts differential cross sections for production of single-inclusive hadronic jets and jet pairs at next-to-leading order (NLO) accuracy in a perturbative QCD calculation. We describe MEKS 1.0, an upgraded EKS program with increased numerical precision, suitable for comparisons to the latest experimental data from the Large Hadron Collider and Tevatron. The program integrates the regularized patron-level matrix elements over the kinematical phase space for production of two and three partons using the VEGAS algorithm. It stores the generated weighted events in finely binned two-dimensional histograms for fast offline analysis. A user interface allows one to customize computation of inclusive jet observables. Results of a benchmark comparison of the MEKS program and the commonly used FastNLO program are also documented. Program SummaryProgram title: MEKS 1.0Catalogue identifier: AEOX_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEOX_v1_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland.Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 9234No. of bytes in distributed program, including test data, etc.: 51997Distribution format: tar.gzProgramming language: Fortran (main program), C (CUBA library and analysis program).Computer: All.Operating system: Any UNIX-like system.RAM: ∼300 MBClassification: 11.1.External routines: LHAPDF (https://lhapdf.hepforge.org/)Nature of problem: Computation of differential cross sections for inclusive production of single hadronic jets and jet pairs at next-to-leading order accuracy in perturbative quantum chromodynamics.Solution method: Upon subtraction of infrared singularities, the hard-scattering matrix elements are integrated over available phase space using an optimized VEGAS algorithm. Weighted events are generated and filled into a finely binned two-dimensional histogram, from which the final cross sections with typical experimental binning and cuts are computed by an independent analysis program. Monte Carlo sampling of event weights is tuned automatically to get better efficiency.Running time: Depends on details of the calculation and sought numerical accuracy. See benchmark performance in Section 4. The tests provided take approximately 27 min for the jetbin run and a few seconds for jetana.