Award Address (Glenn T. Seaborg Award for Nuclear Chemistry, sponsored by ACS Division of Nuclear Chemistry and Technology). Probing the birth of clusters in a warm and dilute nuclear medium with correlation functions

NUCL 39

Romualdo de Souza, desouza@indiana.edu, Department of Chemistry, Indiana University, Bloomington, IN 47405
Cluster formation in the nuclear medium is a highly interesting phenomenon. Heavy nuclei spontaneously emit alpha particles from the nuclear surface. Excited nuclei emit both light clusters (Z$\le$2) as well as heavier clusters (Z$>$2). These clusters may be excited and subsequently undergo particle decay. Peaks in the relative energy spectrum of the secondary decay products indicate resonance, reflecting the discrete internal structure of the primary emitted cluster. Resonance spectroscopy can be used, for example, to determine the temperature of the initial source within a statistical approach. To date however, the effect of the field of the emitting nucleus on the decay of the cluster has been largely neglected. For short-lived states the cluster is expected to decay in the vicinity of the nuclear surface. Such proximity decay exhibits a tidal effect, namely the correlation of the relative energy of the daughter products with the decay angle relative to the emission direction. We explore the influence of the external field (both Coulomb and nuclear) on the decay of the first excited state of 8Be emitted from the projectile-like fragment in the reaction 114Cd + 92Mo at E/A=50 MeV. Comparison of experimental data with the predictions of a simple trajectory model indicate a sensitivity to the interaction of the nuclear surface with the emitted cluster.