Calculations of large mass fragment yields from high-energy heavy-ion reactions are performed based on the abrasion-ablation model. The geometrical picture of the clean-cut fireball model is used to calculate the number of participant nucleons in the abrasion stage and the excitation energy of the spectators (primary residues). A standard statistical evaporation code is used to calculate the ablation stage. Results from this model show an overall agreement with experimental data, although some systematic discrepancies are found and discussed. A frictional spectator interaction is introduced which increases the average excitation energy of primary fragments and improves the results considerably.NUCLEAR REACTIONS Relativistic Heavy-ions, abrasion-ablation model, ' peripheral reactions, calculated fragmentation cross sections.

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The possibility of observing previously postulated neutron-proton correlations in the nuclear ground state via relativistic heavy-ion reactions is examined. The isotope-production cross sections from the reaction of 213-MeV/nucleon 40 Ar with 12 C are calculated with a correlated abrasion-ablation model and with an uncorrelated intranuclear cascade model, and the results compared to recent experimental data. The neutron-proton correlations may only be visible in products near the mass of the fragmenting nucleus.