PHANTOM: A Monte Carlo event generator for six parton final states at high energy colliders

PHANTOM is a tree level Monte Carlo for six parton final states at proton-proton, proton-anti proton and electron-positron colliders at O(alpha(6)(EM)) and O(alpha(4)(EM)alpha(2)(S)) including possible interferences between the two sets of diagrams. This comprehends all purely electroweak contributions as well as all contributions with one virtual or two external gluons. It can generate unweighted events for any set of processes and it is interfaced to parton shower and hadronization packages via the latest Les Houches Accord protocol. It can be used to analyze the physics of boson-boson scattering, Higgs boson production in boson-boson fusion, IF and three boson production. Program summary Program title: PHANTOM (V. 1-0) Catalogue identifier. AECE_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AECE-v1-0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 175 787 No. of bytes in distributed program, including test data, etc.: 965 898 Distribution format: tar.gz Programming language: Fortran 77 Computer. Any with a UNIX, LINUX compatible Fortran compiler Operating system: UNIX, LINUX RAM. 500 MB Classification: 11.1 External routines: LHAPDF (Les Houches Accord PDF Interface, http://projects.hepforge.org/lhapdf/), CIRCE (beamstrahlung for e(+)e(-) ILC collider). Nature of problem: Six fermion final state processes have become important with the increase of collider energies and are essential for the study of top, Higgs and electroweak symmetry breaking physics at high energy colliders. Since thousands of Feynman diagrams contribute in a single process and events corresponding to hundreds or different final states need to be generated, a fast and stable calculation is needed. Solution method: PHANTOM is a tree level Monte Carlo for six parton final states at proton-proton, proton-anti proton and electron-positron colliders. It computes all amplitudes at O(alpha(6)(EM)) and O(alpha(4)(EM)alpha(2)(S)) including possible interferences between the two sets of diagrams. The matrix elements are computed with the helicity formalism implemented in the program PHACT [1]. The integration makes use of an iterative-adaptive multichannel method which, relying on adaptivity. allows the use of only a few channels per process. Unweighted event generation can be performed for any set of processes and it is interfaced to parton shower and hadronization packages via the latest Les Houches Accord protocol. Restrictions: All Feymman diagrams are computed al LO. Unusual features: Phantom is written in Fortran 77 but it makes use of structures, The g77 compiler cannot compile it as it does not recognize the structures. The Intel, Portland Group, True64 HP Fortran 77 or Fortran 90 compilers have been tested and can be used. Running time: A few hours for a cross section integration of one process at per mille accuracy. One hour for one thousand unweighted events.