Correlation and Fluctuation in Multiparticle Production: Some Closing Remarks

I was asked to close this Workshop with some comments that can give a historical perspective of the series. I will therefore not attempt to summarize the talks that have been presented here. This series of workshops have been held over the span of about twenty years, and I happen to be the only one who has been to all eleven of them. The titles and contents of the workshops have varied over the years, but the invariant theme has always been about multiparticle production. The first workshop held in Aspen in 1986 was a very small one and did not have the format that has been customary for all others in the series. There were no proceedings to look back to. The first formal one was held in Jinan, China in the following year, organized by Q.-B. Xie and me. In the prologue to the proceedings I wrote: “Multiparticle production is regarded by particle physicists as being too complicated and therefore declared uninteresting. · · · The malaise is basically an internal one. The absence of a workable theory gave rise to a proliferation of models, many of which bear little resemblance to one another. · · · The field not only has no first principles to rely on, · · · it has generated no collective wisdom to serve as a guide to the construction of models.” In the International Conference on High Energy Physics (Berkeley, 1986) there was not one session devoted exclusively to soft hadronic processes and multiparticle production. The need for a workshop was obvious. The situation today is totally reversed in the nuclear physics community, where the complexity of a collisional system does not pose a barrier to the motivated investigators, and where the applicability of relativistic hydrodynamics to heavy-ion collisions provides a successful theoretical basis for the description of the evolutionary properties of the bulk matter, in essentially the same framework formulated by Landau1 and Bjorken2 for hadronic collisions. The issue is no longer how to describe the collision process, but what we can learn from the hydrodynamical parameters and how to understand the features that cannot be explained by hydrodynamics. This Workshop on correlation and fluctuation is aimed at addressing precisely those