Target fragmentation at ultrarelativistic energies

We have used 200 GeV/u and 60 GeV/u oxygen beams accelerated at CERN to bombard a 1.5 mg/cm2 Au target. Light nuclei have been detected at 250 and 550 using silicon telescopes. Their inclusive mass distribution follows an exponential behaviour at 200 GeV/u but is different at 60 GeV/u. In this latter case the situation is similar to what has been observed at lower bombarding energies with heavy ions, and for high energy proton-induced reactions. The results at 200 GeV/u are, however, different from those observed in proton-induced reactions in the same energy domain. (orig.)