Prerequesites

The basic installation requires GNU make, a FORTRAN 95 (we have tested gfortran and ifort) and a C++ compiler. VBFNLO offers the possibility of using the LHAPDF library for parton distribution functions. In order to include the electroweak corrections, the program LoopTools is required. Additionally, FeynHiggs can be linked to the code in order to calculate the Higgs boson sector of the MSSM, although a SLHA file can be used as an alternative. If the simulation of Kaluza-Klein resonances is enabled, an installation of the GNU Scientific Library GSL is required. VBFNLO can also be linked to ROOT and HepMC to produce histograms and event files in those formats.

Compilation

After unpacking the source archive and entering the source directory, the configure script can be invoked with several options, a complete list being available via ./configure --help. Among these, the most important ones are:

--prefix=[path]

Install VBFNLO in the location given by [path].

--enable-processes=[list]

By default, the code for processes that do not contain hexagons (i.e. all processes except triboson + jet processes) are compiled. Optionally, [list] gives a comma separated list of selected processes to be compiled. Possible names are:

• vbf - Vector boson processes,
• qcdvjj - QCD-induced vector boson plus two jet production,
• qcdvvjj - QCD-induced vector boson pair plus two jet production,
• diboson - Double gauge boson production, including W and WH production,
• triboson - Triple gauge boson production,
• dibosonjet - Double gauge boson production with a hadronic jet, including Wj and WHj production,
• tribosonjet - Triple gauge boson production with a hadronic jet,
• hjjj - Higgs boson plus three jet production in vector boson fusion,
• ggf - Higgs boson plus two jet via gluon fusion,
• all_except_hexagons - All the above processes except those with hexagon contributions (default),
• all - All of the above processes.

--disable-NLO

Disable the next-to-leading order QCD corrections.

--enable-kk

Enable simulation of Kaluza-Klein resonances. Disabled by default, the Kaluza-Klein option requires the installation of the GNU Scientific Library, which can be specified via --with-gsl.

--enable-spin2

Enable simulation of spin-2 resonances. Disabled by default.

--with-gsl=[path]

Enable use of the GNU Scientific Library. [path] specifies the location of the GSL installation. If the GSL is available directly from the system libraries this flag can be omitted.

--with-LHAPDF=[path]

Enable the use of LHAPDF instead of the built-in PDF sets. Disable by default. [path] specifies the location of the LHAPDF installation.

--with-LOOPTOOLS=[path]

Enable the use of LoopTools in order to calculate the electroweak corrections. If this option is not specified, the electroweak corrections cannot be included. Disable by default. [path] specifies the location of the LoopTools installation.

--with-FEYNHIGGS=[path]

Enable the use of FeynHiggs to calculate the MSSM Higgs sector parameters. Disabled by default. [path] specifies the location of the FeynHiggs installation.

--with-root=[path]

Enable the use of Root. [path] specifies the location of the Root installation.

--with-hepmc

Enable the production of HepMC format event files. [path] specifies the location of the HepMC installation.

--enable-MPI

Enables MPI parallelization. In order to use this option OpenMPI must be installed in your system and be available in the environment. Moreover, the corresponding compiler wrappers must be passed to the configure script i.e. FC=mpifort CC=mpicc CXX=mpic++.

Note that, by default, both LoopTools and FeynHiggs are installed as static libraries. If this is the case, configure must be run with the option --enable-shared=no. Also note that, in order to link to an external program such as LoopTools, the external program needs to have been compiled using the same compiler (e.g. gfortran) as VBFNLO. Once configure has been finished successfully, the make and make install commands will compile and install VBFNLO, respectively.

The source does not need to be modified to change the simulation parameters. VBFNLO offers several kinematic cuts and scale choices via input files. These are described in the manual. In addition, it provides a few basic histograms. Cuts, histograms and scale choices not already provided may be added in the utilities/cuts.F, utilities/histograms.F and utilities/scales.F files.

Installation

The installation is performed in a standard Unix-layout, i.e. the directory specified with the --prefix option of the configure script contains the following directories:

• bin/: vbfnlo executable.
• include/VBFNLO/: VBFNLO header files.
• lib/VBFNLO/: VBFNLO modules as dynamically loadable libraries. These can also be used independently from one of the main programs.
• share/VBFNLO/: Input files and internal PDF tables.