1998/03/10 by R. Nouicer, Ch. Beck, Nouicer, R. +11
Physics and Astronomy · #Atomic and Molecular Physics #FOS: Physical sciences #Nuclear Experiment (nucl-ex) #Nuclear physics research studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.nucl-ex/9803005
openalex publication_date 1998/03/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Fragment-fragment-γ triple coincidence measurements of the 28Si~+~28Si reaction at E\rm c.m.~=~55.8 MeV, carefully chosen to populate a well known quasi-molecular resonance in 56Ni, have been performed at the VIVITRON tandem facility by using the Eurogam Phase~II γ-ray spectrometer. In the 28Si~+~28Si reaction, the resonant behavior of the 28Si + 28Si exit-channel is clearly observed by the present fragment-fragment coincidence data. The more unexpected result is the spin disalignment of the 28Si + 28Si resonance. This has been demonstrated first by the measured angular distributions of the elastic 0+, inelastic 2+ and mutual excitation channels 2+-2+, which are dominated by a unique and pure partial wave with L = 38 \rm ℏ, and has been confirmed by measuring their particle-γ angular correlations with Eurogam Phase II. The spin disalignment supports new molecular model predictions, in which the observed resonance would correspond to the ''Butterfly mode''. A discussion concerning the \it spin alignment and spin disalignment for different systems : 12C~+~12C, 24Mg~+~24Mg and 28Si~+~28Si will be given.