Influence of the density of states on the odd-even staggering in the charge distribution of the emitted fragments in nuclear heavy-ion collisions

• Autor(a) principal: Calleya, Natália de Lima
• Data de Publicação: 2014
• Outros Autores: Souza, Sergio Ricardo de Azevedo, Carlson, Brett Vern, Donangelo, Raul José, Lynch, William G., Tsang, M. B., Winkelbauer, J. R.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRGS
• Texto Completo: http://hdl.handle.net/10183/107949
• topic: Densidade nuclear; Fragmentação nuclear; Termodinâmica nuclear; Carga nuclear; Níveis nucleares de energia; Teoria de decaimento nuclear

The fragmentation of thermalized sources is studied using a version of the Statistical MultifragmentationModel which employs state densities that take the pairing gap in the nuclear levels into account. Attention is focused on the properties of the charge distributions observed in the breakup of the source. Since the microcanonical version of the model used in this study provides the primary fragment excitation energy distribution, one may correlate the reduction of the odd-even staggering in the charge distribution with the increasing occupation of high-energy states. Thus, in the framework of this model, such staggering tends to disappear as a function of the total excitation energy of the source, although the energy per particle may be small for large systems. We also find that, although the deexcitation of the primary fragments should, in principle, blur these odd-even effects as the fragments follow their decay chains, the consistent treatment of pairing may significantly enhance these staggering effects on the final yields. In the framework of this model, we find that odd-even effects in the charge distributions should be observed in the fragmentation of relatively light systems at very low excitation energies. Our results also suggest that the odd-even staggering may provide useful information on the nuclear state density.