The History of BUU Codes at Gießen

Our interest in transport calculations started with a sabbatical visit of Ulrich Mosel at Michigan State University during spring/summer of 1986. During this time also the Giessen PhD student Wolfgang Bauer spent some time there, under the guidance of George Bertsch, but working for a degree at Giessen. While George had written one of the very first BUU codes, 'quick and dirty', Wolfgang Bauer rewrote this code and during Mosel's visit at MSU the first calculations of particle production, in this case photons, were done and later published. With Wolfgang Bauer the very first Giessen BUU code returned to Giessen. From then on a number of very good young scientists have worked on it. Wolfgang Cassing joined the effort at this point. First, Koji Niita (Japan) rewrote again large parts of the code and implemented pion production and a good description of the nuclear ground state, Angel de Paoli and Gustavo Batko (both Argentina) used it to calculate etas and kaons produced in heavy-ion collisions and Gyuri Wolf (Hungary) did a series of important papers on dilepton production which provided some of the motivation for the construction of HADES, the dilepton spectrometer at GSI. Very early on, a parallel development to construct a manifestly covariant BUU code was started. Giessen PhD students Volker Koch and Bernhard Blaettel wrote the first such code and used it to analyse BEVALAC cata on flow and particle production. Klaus Weber in his thesis did work on a covariant description of the momentum dependence of the mean field at high energies, where the Walecka model becomes too repulsive. Tomoyuki Maruyama (Japan) followed up on this and did the first numerical implementation of this explicit momentum dependence. ...MORE TO COME