Breakup ofO16intoBe8+

Pierre Chevallier

¹

,

F. Scheibling

²

,

G. Goldring

³

et al.

Linear-chain structure of three α clusters inC13

“…The state is gaslike without a specific geometric shape, and it has been recently reinterpreted as an α-condensed state [4]. The search for linear-chain states of α clusters has been extended to heavier N = Z nuclei [5][6][7][8]; however, further investigations are needed to confirm that those states are really linear-chain structures.The difficulty of the linear-chain configuration is briefly explained in the following way. From the harmonic-oscillator point of view, if three α clusters form a linear configuration on the z axis, four nucleons in the central α cluster occupy the lowest s orbits; however, eight nucleons in the other α clusters are excited to higher orbits such as the p(z) and sd(z 2 ) orbits due to the antisymmetrization effect.…”

“…The state is gaslike without a specific geometric shape, and it has been recently reinterpreted as an α-condensed state [4]. The search for linear-chain states of α clusters has been extended to heavier N = Z nuclei [5][6][7][8]; however, further investigations are needed to confirm that those states are really linear-chain structures.…”

Binary reaction decays fromMg24+C12

“…However, any state in 16 O equivalent to the so-called Hoyle state in 12 C is most certainly going to decay by particle emission, with very small, probably unmeasurable γ -decay branches. Very efficient particle-detection techniques will have to be used in the near future, as such BEC states will be expected to decay by α emission to the Hoyle state, and could be associated with resonances in α-particle inelastic scattering on 12 C leading to that state, or be observed in α-particle transfer to the 8 Be- 8 Be final state as observed by Chevallier and coworkers back in the 1960s [71]. Another possibility might be to perform Coulomb excitation measurements with intense 16 O beams at intermediate energies.…”

New Horizons in Fundamental Physics

“…BEC states are expected to decay by alpha emission to the "Hoyle" state and could be found among the resonances in α-particle inelastic scattering on 12 C decaying to that state. In 1967 Chevallier et al [38] could excite these states in an α-particle transfer channel leading to the 8 Be- 8 Be final state and proposed that a structure corresponding to a rigidly rotating linear arrangement of four alpha particles may exist in 16 O. Very recently, a more sophisticated experimental setup was used at Notre Dame [39]: although the excitation function is generally in good agreement with the previous results [38] a phase shift analysis of the angular distributions does not provide evidence to support the reported hypothesis of a 4α-chain state configuration.…”

“…In 1967 Chevallier et al [38] could excite these states in an α-particle transfer channel leading to the 8 Be- 8 Be final state and proposed that a structure corresponding to a rigidly rotating linear arrangement of four alpha particles may exist in 16 O. Very recently, a more sophisticated experimental setup was used at Notre Dame [39]: although the excitation function is generally in good agreement with the previous results [38] a phase shift analysis of the angular distributions does not provide evidence to support the reported hypothesis of a 4α-chain state configuration. Experimental investigations are still underway to understand the nuclear structure of high spin states of both 16 O and 20 Ne nuclei for instance at Notre Dame and/or iThemba Labs [40] facilities.…”