Dedicated to the Memory of Klaus Kinder-Geiger

Final Program

Preliminary List of Speakers

Motivation

Hard partons, or jets, in relativistic heavy-ion collisions can serve as "hard probes" of the dense matter environment produced in collisions of nuclei, for instance by tagging them with a photon. Hard partons in heavy-ion collisions may therefore be used in two ways: first, actively, as a "densometer" probing the medium, and second, passively, as quanta that are modified by the medium. That is, both the properties of the medium (using hard partons as probing objects), as well as the modification of jets inside a medium (using hard partons as study objects) may be investigated.

As the RHIC facility is approaching its completion, it is particularly important to concentrate the effort of researchers working in this field -- we have to scrutinize the existing knowledge and to work out the predictions and suggestions for the experiments before RHIC begins its operation in 1999. Confronting pre--, rather than post--dictions with the RHIC data will give us much firmer confidence in our understanding of the underlying physics, and can significantly advance the theory.

Purpose of the Workshop

• To bring together expert researchers from high-energy particle physics with colleagues from the heavy-ion physics community, in order to merge the very different physics backgrounds to a joint understanding of high-energy QCD at large densities.
• To discuss critically the existing approaches to jet production and evolution, to establish the conditions of applicability, and the ways to check them against the present and future data.
• To initialize a coordinated effort of working out the concrete predictions for RHIC experiments, to discuss what measurements at RHIC would be particularly useful, and to prepare a compilation of the suggestions and predictions for the experiments at RHIC.

Topics

• What do we know from particle physics (e+e-, gamma gamma, ep, gamma p, pp)?
  • production mechanisms
  • theoretical and experimental accuracy of hard cross-sections
  • structure functions and fragmentation functions
  • correlations among final-state particles
• How to define and to identify hadronic jets as manifestations of partonic hard processes?
  • experimental backgrounds
  • experimental jet-finding techniques (one/several leading particle(s), mother of jet)
  • theoretical jet-finding algorithms (based on knowledge of parton evolution)
  • parton fragmentation (universal or different in e+e-, pp, pA, and in AB with/without quark-gluon plasma)
• High-pT particle spectra and ET production
  • Observable differences for scenarios with and without hard partons/jets
  • Effects of dense matter on hadron spectra from fragmented partons/jets
• Jets in central collisions versus peripherical collisions
  • how to calibrate medium effects as a function of centrality
• Energy (root(s)) dependence, and system size (AB)
  • how does variation of those affect hard parton/jet properties
• Subtleties of hard parton evolution and fragmentation
  • quark jets versus gluon jets
  • energy-loss and pT-broadening
  • local density increase due to reinteractions of emitted gluons in vicinity of jet cone
  • flavor/charge of leading particle