HERWIG 6: an event generator for hadron emission reactions with interfering gluons (including supersymmetric processes)

HERWIG is a general-purpose Monte Carlo event generator, which includes the\nsimulation of hard lepton-lepton, lepton-hadron and hadron-hadron scattering\nand soft hadron-hadron collisions in one package. It uses the parton-shower\napproach for initial- and final-state QCD radiation, including colour coherence\neffects and azimuthal correlations both within and between jets. This article\nupdates the description of HERWIG published in 1992, emphasising the new\nfeatures incorporated since then. These include, in particular, the matching of\nfirst-order matrix elements with parton showers, a more correct treatment of\nheavy quark decays, and a wide range of new processes, including many predicted\nby the Minimal Supersymmetric Standard Model, with the option of R-parity\nviolation. At the same time we offer a brief review of the physics underlying\nHERWIG together with details of the input and control parameters and the output\ndata, to provide a self-contained guide for prospective users of the program.\nThis version of the manual (version 3) is updated to HERWIG version 6.5, which\nis expected to be the last major release of Fortran HERWIG. Future developments\nwill be implemented in a new C++ event generator, HERWIG++.\n