PYTHIA is a program for the generation of high-energy physics events, i.e. for the description of collisions at high energies between elementary particles such as e+, e-, p and pbar in various combinations. It contains theory and models for a number of physics aspects, including hard and soft interactions, parton distributions, initial- and final-state parton showers, multiple interactions, fragmentation and decay. It is largely based on original research, but also borrows many formulae and other knowledge from the literature.

WWW: http://home.thep.lu.se/~torbjorn/Pythia.html
