Nuclear Fireball Model for Proton Inclusive Spectra from Relativistic Heavy-Ion Collisions

A simple model is proposed for the emission of nucleons with velocities intermediate between those of the target and projectile. In this model, the nucleons which are mutually swept out from the target and projectile form a hot quasiequilibrated fireball which decays as an ideal gas. The overall features of the proton-inclusive spectra from 250- and 400-MeV/nucleon ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ ions and 400-MeV/nucleon ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ ions interacting with uranium are fitted without any adjustable parameters.