MCFM

MCFM
Name	MCFM
Genre	Computational software
Developed by	Various academic groups
Initial release	1990s
Programming language	Fortran, C++
Operating system	Unix-like, Linux, macOS
License	Academic

MCFM MCFM is a widely used perturbative quantum field theory program for calculating fixed-order cross sections in collider processes. It interfaces with parton distribution functions and Monte Carlo tools to produce predictions for experiments at facilities such as Large Hadron Collider, Tevatron, CERN, Fermilab and to compare with results from collaborations like ATLAS experiment, CMS experiment, DØ experiment, and CDF experiment. The project builds on methods from perturbative Quantum Chromodynamics, Electroweak interaction computations, and resummation studies associated with theoretical groups at institutions such as Oxford University, University of Cambridge, Princeton University, Massachusetts Institute of Technology, and DESY.

Overview

MCFM implements fixed-order matrix element calculations for processes relevant to proton–proton collision, proton–antiproton collision, and related hadron collider environments. It provides next-to-leading order (NLO) predictions for vector boson production, heavy-flavor production, diboson processes, and associated Higgs boson channels studied by collaborations including LHCb experiment, ALICE experiment, Belle II, SLAC National Accelerator Laboratory, and Brookhaven National Laboratory. The software connects with parton distribution sets maintained by groups such as CTEQ, MSTW, NNPDF, HERAPDF, and computational frameworks like LHAPDF, FastJet, and ROOT.

History and Development

Development traces to perturbative calculations performed during the era of comparisons between predictions and data from the Large Electron–Positron Collider and early Tevatron runs. Key methodological advances echo work by theorists associated with institutions like Harvard University, Stanford University, University of California, Berkeley, Imperial College London, Columbia University, University of Zurich, ETH Zurich, University of Edinburgh, and research centers such as Institut de Physique Théorique, Max Planck Institute for Physics, and Kavli Institute for Theoretical Physics. Contributions align with formalisms developed in landmark collaborations connected to awards such as the Nobel Prize in Physics for work on the Higgs boson and theoretical frameworks influenced by results from the Tevatron collider and the LEP experiments. Over successive releases MCFM incorporated modern subtraction schemes, loop libraries and automated amplitude techniques inspired by work at CERN Theory Department, Perimeter Institute, Institute for Advanced Study, and groups led by researchers from Rutgers University and Yale University.

Theoretical Framework and Features

MCFM is grounded in perturbative Quantum Chromodynamics and Electroweak interaction calculations at fixed order, using renormalization and factorization schemes developed in legacy papers from groups at Princeton, Caltech, University of Chicago, University of Michigan, University of Oxford, University of Cambridge, University of Toronto, McGill University, and Lyon Institute of Nuclear Research. It supports NLO corrections for processes including Drell–Yan process, top quark pair production, single top production studied at Fermilab, vector boson scattering channels relevant to ATLAS experiment and CMS experiment, and Higgs-associated production modes probed at CERN. The code employs subtraction methods related to the Catani–Seymour dipole subtraction formalism and alternatives developed in collaborations involving Nikhef, CEA Saclay, INFN, University of Milan, and Università di Padova.

Computational Implementation and Tools

The codebase is written primarily in Fortran and C++ and compiles on Linux and macOS systems using toolchains like GCC, Clang, and build systems influenced by CMake practices. It links to numerical libraries such as LHAPDF for parton distributions, LoopTools and QCDLoop for loop integrals, and integrates with event-level tools like HEPMC and analysis frameworks such as ROOT and Rivet. Workflows typically run on computing clusters at facilities like CERN OpenStack, National Energy Research Scientific Computing Center, NERSC, GridPP, and national grid infrastructures used by ATLAS and CMS. Interoperability with matching and merging schemes relates to tools like POWHEG BOX, MC@NLO, Sherpa, MadGraph, Herwig, Pythia, and tuning results from groups at Monash University and DESY.

Applications in High-Energy Physics

MCFM predictions are applied in precision measurements of electroweak parameters, top-quark mass determinations undertaken by CDF experiment and DØ experiment, Higgs coupling studies by ATLAS experiment and CMS experiment, and searches for beyond-Standard-Model signatures pursued by collaborations at CERN. Analysts use MCFM for background estimates in searches reported by experiments including LHCb experiment, ALICE experiment, and in joint publications with theory groups at SLAC, DESY, KEK, TRIUMF, and J-PARC. Results feed into global PDF fits coordinated by groups such as CTEQ, NNPDF, and MMHT, and into phenomenological studies appearing in journals connected to Physical Review Letters, Journal of High Energy Physics, and proceedings of conferences like International Conference on High Energy Physics and workshops at CERN Theory Division.

Validation and Comparisons

MCFM validations compare fixed-order outputs with analytic results derived by collaborations at Institut des Hautes Études Scientifiques, Max Planck Institute, and algorithmic benchmarks from projects like NNLOJET, FEWZ, MCFM comparisons with POWHEG BOX, and cross-checks against event generators MadGraph5_aMC@NLO and Sherpa. Comparison studies are presented in publications and at meetings hosted by EPS-HEP, Moriond, Les Houches workshops, and working groups convened by LHC Physics Center and Theory@CERN to ensure consistency with experimental measurements from ATLAS experiment and CMS experiment.

Category:Particle physics software