Reaction mechanisms in 28Si+24Mg--> alpha +24Mg+24Mg and alpha +20Ne+28Si.

Abstract

We have studied the $^{28}$Si${+}^{24}$Mg system leading to the three-body final states \ensuremath{\alpha}${+}^{24}$Mg${+}^{24}$Mg and \ensuremath{\alpha}${+}^{20}$Ne${+}^{28}$Si. Full momentum reconstruction on an event by event basis allows us to obtain all kinematic quantities, and perform a comparison of competing reaction mechanisms. A search reveals very little evidence for the population of high-spin states in $^{48}\mathrm{Cr}$ corresponding to resonances observed in the $^{24}$Mg${+}^{24}$Mg system, via the $^{24}\mathrm{Mg}$${(}^{28}$Si,\ensuremath{\alpha}${)}^{48}$${\mathrm{Cr}}^{\mathrm{*}}$${(}^{24}$Mg) and $^{24}\mathrm{Mg}$${(}^{28}$Si,\ensuremath{\alpha}${)}^{48}$Cr*${(}^{20}$Ne) reactions. Instead, we find that the dominant processes that occur involve inelastic heavy-ion scattering to \ensuremath{\alpha}-particle unbound states in $^{28}\mathrm{Si}$ and $^{24}\mathrm{Mg}$.