Light-Charged-Particle Emission in the Matched Reactions 280 MeV 40Ar+27A1 and 670 MeV 55Mn-+12C: Inclusive studies

In order to test the statistical model’s ability to predict the behavior of relatively light mass systems (A≈67) with large angular momenta, two matched heavy ion nuclear reactions were used to produce 67Ga* composite nuclei at an excitation energy of 127 MeV. Light charged particles (protons, deuterons, tritons, and α particles) were used as probes to characterize the composite systems and track the deexcitation processes. From these measurements, energy spectra, cross sections, angular distributions, anisotropy ratios, and particle multiplicities were deduced. Measuring many degrees of freedom provides a stringent test for the statistical models. What is found is that models which did well in predicting the behavior of heavy composite systems (A≈150), are unable to simultaneously reproduce energy spectra, angular distributions, and particle multiplicities for the lighter systems (A≈67), where angular momentum plays a dominant role. This implies that more rigorous models and/or additional physics are needed to understand the behavior of the hot, high-spin nuclear matter in this mass region