Some thoughts about experiments in the fragmentation region

The results of some discussions about possible experiments in the fragmentation region are presented. At RHIC energies one expects the baryon-rich regions to be within, say, 3 units of the beam rapidity, so that the fragmentation region is defined as absolute value of y > 3 or theta < 5.70. Meanwhile the first results from experiments at the AGS and CERN have provided evidence that energy densities predicted to be necessary for plasma formation are already reached in fixed target experiments at energies where there is still substantial stopping. In such experiments the central region is baryon-rich and studies of it should yield information similar to what can be obtained from the fragmentation region at RHIC. In view of this new development the authors have tried to reassess the physics goals of an experiment covering the fragmentation region at RHIC. Some of the findings are listed below: (i) Quark gluon plasma formation in the fragmentation region should be strongly correlated with plasma formation in the central region. (ii) There are observables for plasma formation in the RHIC fragmentation region which might yield information different from that obtained by studies of the baryon-rich central region at CERN or AGS energies. (iii) There is clearly an interest in dedicated smaller set-ups to study specific observables in the fragmentation region. 3 references