Impact parameter and energy dependence of observables in intermediate energy heavy-ion reactions

The dependence of various measurable properties of heavy-ion collisions is calculated with the Boltzmann equation, in an attempt to find the best observables to determine the impact parameter in a collision. The observables considered are multiplicity of fast nucleons longitudinal momentum transfer, angular momentum transfer, projectile mass loss, and projectile energy loss. Systems studied in detail include the ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ ${+}^{154}$Sm reaction at E/A=35 MeV, the ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$ ${+}^{197}$Au reaction at E/A=60 MeV, and the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ ${+}^{197}$Au reaction at E/A=90 MeV where some experiments have been performed with reaction filters. The energy and impact parameter dependence of nucleon multiplicity distributions have also been studied for the mass symmetric ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$ ${+}^{40}$Ar and asymmetric ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ ${+}^{197}$Au systems at energies ranging from E/A=35 to 400 MeV. These calculations suggest that the mean multiplicity of fast nucleons and the linear momentum transferred to the target residue are relatively insensitive to the impact parameter at small impact parameters and incident energies below E/A≤60 MeV. These nucleon multiplicity distributions become more sensitive to impact parameters with increasing incident energy and may provide rather accurate impact parameter information for incident energies as large as E/A≊90 MeV.