W physics at the LHC with FEWZ 2.1

Abstract

We present an updated version of the FEWZ (Fully Exclusive W and Z production) code for the calculation of W± and γ∗/Z production at next-to-next-to-leading order in the strong coupling. Several new features and observables are introduced, and an order-of-magnitude speed improvement over the performance of FEWZ 2.0 is demonstrated. New phenomenological results for W± production and comparisons with LHC data are presented, and used to illustrate the range of physics studies possible with the features of FEWZ 2.1. We demonstrate with an example the importance of directly comparing fiducial-region measurements with theoretical predictions, rather than first extrapolating them to the full phase space. Program summaryProgram title: FEWZ 2.1Catalogue identifier: AEJP_v1_1Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEJP_v1_1.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 12003230No. of bytes in distributed program, including test data, etc.: 769Distribution format: tar.gzProgramming language: Fortran 77, C++, Python 2.4.Computer: x86/x86-64.Operating system: Unix/Linux, Mac OSX.RAM: 200 MbytesClassification: 11.1.External routines: CUBA (included), LHAPDF (optional)Catalogue identifier of previous version: AEJP_v1_0Journal reference of previous version: Comput. Phys. Comm. 182 (2011) 2388Does the new version supersede the previous version?: YesNature of problem: Calculation of hadroproduction of W bosons, with differential distributions, at next-to-next-to-leading order in the strong coupling.Solution method: Integral reduction, sector decomposition, numerical integrationReasons for new version: Reintroduction of W boson to FEWZ 2Summary of revisions: Addition of W boson production, now can run in W or Z/gamma mode. LHAPDF interface added. Large speed improvements achieved through caching repeat function calls. New observables and histograms. Improved histogram binning.Additional comments: Running with all histograms on requires approx. 1 GB of disk space to store intermediate files.!!!!! The distribution file for this program is over 290 Mbytes and therefore is not delivered directly when download or e-mail is requested. Instead an html file giving details of how the program can be obtained is sent.!!!!!Running time: 2 hours to achieve NNLO precision in cross section on multicore machines, up to a few days for quality kinematic distributions. Cluster running is considerably faster.