Program Overview

This section contains a diverse collection of information. The first part is an overview of previous JETSET and PYTHIA versions. The second gives instructions for installation of the program and describes its philosophy: how it is constructed and how it is supposed to be used. It also contains some information on how to read this manual. The third and final part contains several examples of pieces of code or short programs, to illustrate the general style of program usage. This last part is mainly intended as an introduction for completely new users, and can be skipped by more experienced ones.

The combined PYTHIA package is completely self-contained. Interfaces to externally defined subprocesses, parton-distribution function libraries, $\tau$ decay libraries, and a time routine are provided, however, plus a few other optional interfaces.

Many programs written by other persons make use of PYTHIA, especially the string fragmentation machinery. It is not the intention to give a complete list here. A majority of these programs are specific to given collaborations, and therefore not publicly distributed. Below we give a list of a few public programs from the `Lund group', which may have a somewhat wider application. None of them are supported by the PYTHIA author team, so any requests should be directed to the persons mentioned.

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ARIADNE is a generator for dipole emission, written mainly by L. Lönnblad [Pet88].

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AROMA is a generator for heavy-flavour processes in leptoproduction, written by G. Ingelman, J. Rathsman and G. Schuler [Ing88].

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FRITIOF is a generator for hadron-hadron, hadron-nucleus and nucleus-nucleus collisions [Nil87].

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LEPTO is a leptoproduction event generator, written mainly by G. Ingelman [Ing80]. It can generate parton configurations in Deeply Inelastic Scattering according to a number of possibilities.

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POMPYT is a generator for pomeron interactions written by G. Ingelman and collaborators [Bru96].

One should also note that a version of PYTHIA has been modified to include the effects of longitudinally polarized incoming protons. This is the work of St. Güllenstern et al. [Gül93].