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Manuscript Title: The Lund Monte Carlo for jet fragmentation and e+e- physics - JETSET version 6.2.
Authors: T. Sjostrand
Program title: JETSET 6.2
Catalogue identifier: AAFP_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 39(1986)347
Programming language: Fortran.
Computer: ND-570.
Operating system: SINTRAN III - VSX/500.
RAM: 50K words
Word size: 32
Keywords: Elementary, Particle physics, Jet fragmentation, Hadronization, Multiparticle production, Quark jet, Gluon jet, E+e- annihilation, Parton showers, Onium decays, Event analysis, Cluster algorithm, Low-pt physics, Monte carlo simulation, Event simulation.
Classification: 11.2.

Nature of problem:
The theory of strong interactions, QCD, can not be solved to describe the process of hadronization, i.e. how the primary partons are transformed into the observable hadrons in high energy interactions. The probability for a given primary parton configuration is often known from perturbative QCD, however.

Solution method:
A phenomenological model, the Lund string model, is introduced to describe the hadronization of an initial parton configuration. Different independent fragmentation schemes are presented as alternatives. Subsequent particle decays are also considered. For e+e- annihilation, the parton configuration probability distributions are implemented. A number of general utility routines are also included. The program presented here represents an upgraded version of AAVM and AAVJ.

At very high energies, the program may break down for one of two reasons, either the number of particles may exceed the memory space available (2000 particles, including the initial partons and unstable, intermediate particles), or the single-precision kinematics may give unacceptable roundoff errors.

Unusual features:
A random number generator is required.

Running time:
Depends very much on the energy and nature of the system, but is roughly proportional to the number of particles produced. A 40 GeV e+e- annihilation event, with an average of 30 particles (of which 14 are charged) takes approximately 0.05 s.