The MC@NLO Package

Stefano Frixione, Fabian Stoeckli, Paolo Torrielli, Bryan Webber, Chris White


MC@NLO is a Fortran package to implement the eponymous scheme for combining a Monte Carlo event generator with Next-to-Leading-Order calculations of rates for QCD processes.

MC@NLO makes use of the Fortran HERWIG or C++ Herwig++ event generator.

The current (sub)version is MC@NLO 4.07, released on 7 May 2012, which includes all features of subversion 4.06, and gives one the possibility of simulating W+W- production also with non-SM couplings. Furthermore, the codes HepMCFortran.* (written originally by A. Papaefstathiou) are available, which fill the /HEPEVT/ common block using Herwig++ internal information, so as to render straightforward the use of Fortran analysis routines in Herwig++ runs. These codes make use of the HepMC package, which the user will need to install independently. In addition, there are minor changes for compliance with LHAPDF, and some formats for double-precision numbers are changed.

The processes available in this version are those of Higgs boson, single vector boson, vector boson pair, heavy quark pair, single top (with and without associated W or charged Higgs), lepton pair and associated Higgs+W/Z production in hadron collisions.

This version is compatible with Fortran HERWIG 6.5 or higher, which can be obtained from the HERWIG home page. Use of version 6.520 or higher is strongly recommended. See also the HERWIG wiki for latest news and updates.

This version is also compatible with Herwig++, which can be obtained from the Herwig++ home page. The user will have to provide installed versions of Herwig++ and ThePEG. We advise the user to adopt versions 2.4.2 for Herwig++ and 1.6.1 for ThePEG or later. We stress that the options ReconstructionOption=General and InitialInitialBoostOption=LongTransBoost must be used when running Herwig++. These are automatically set by our script, and the user must not change them. The latter option is presently available only in the trunk version of Herwig++ 2.4.2.


Here you can find


If you use MC@NLO, please cite the original publication:

  • S. Frixione and B.R. Webber, Matching NLO QCD computations and parton shower simulations, JHEP 0206 (2002) 029 [hep-ph/0204244]

and those relevant from the following:

  • S. Frixione, P. Nason and B.R. Webber, Matching NLO QCD and parton showers in heavy flavour production, JHEP 0308 (2003) 007 [hep-ph/0305252];
  • S. Frixione, E. Laenen, P. Motylinski and B.R. Webber, Single-top production in MC@NLO, JHEP 0603 (2006) 092 [hep-ph/0512250];
  • S. Frixione, E. Laenen, P. Motylinski, B.R. Webber and C.D. White, Single-top production in association with a W boson, JHEP 0807 (2008) 029 [arXiv:0805.3067].
  • S. Frixione, F. Stoeckli P. Torrielli and B.R. Webber, NLO QCD corrections in Herwig++ with MC@NLO, JHEP 1101 (2011) 053 [arXiv:1010.0568].

The program by B. Fuks, M. Klasen, F. Ledroit, Q. Li and J. Morel implementing Z' production in MC@NLO can be found here.


Last updated BRW 07/05/12