Large Fragment Production Calculations in Relativistic Heavy-ion Reactions. [Abrasion-ablation Model, Cross Sections, Fireball and Firestreak Models]. PDF Download

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

Get Book Here

Book Description
The abrasion-ablation model is briefly described and then used to calculate cross sections for production of large fragments resulting from target or projectile fragmentation in high-energy heavy-ion collisions. The number of nucleons removed from the colliding nuclei in the abrasion stage and the excitation energy of the remaining fragments (primary products) are calculated with the geometrical picture of two different models: the fireball and the firestreak models. The charge-to-mass dispersion of the primary products is calculated using either a model which assumes no correlations between proton and neutron positions inside the nucleus (hypergeometric distribution) or a model based upon the zero-point oscillations of the giant dipole resonance (NUC-GDR). Standard Weisskopf--Ewing statistical evaporation calculations are used to calculate final product distributions. Results of the pure abrasion-ablation model are compared with a variety of experimental data. The comparisons show the insufficiency of the extra-surface energy term used in the abrasion calculations. A frictional spectator interaction (FSI) is introduced which increases the average excitation energy of the primary products, and improves the results considerably in most cases. Agreements and discrepancies of the results calculated with the different theoretical assumptions and the experimental data are studied. Of particular relevance is the possibility of observing nuclear ground-state correlations. Results of the recently completed experiment of fragmentation of 213 Mev/A 4°Ar projectiles are studied and shown not to be capable of answering that question unambiguously. But predictions for the upcoming 48Ca fragmentation experiment clearly show the possibility of observing correlation effects. 78 references.