Evidence for O-15 + alpha resonance structures in Ne-19 via direct measurement

Torresi, D.; Wheldon, C.; Kokalova, T. Z.; Bailey, S.; Boiano, A.; Boiano, C.; Fisichella, M.; Mazzocco, M.; Parascandolo, C.; Pierroutsakou, D.; Strano, E.; Zadro, M.; Cavallaro, M.; Cherubini, S.; Curtis, N.; Di Pietro, A.; Fernã¡ndez Garcia, J. P.; Figuera, P.; Glodariu, T.; Grbosz, J.; La Cognata, M.; La Commara, M.; Lattuada, M.; Mengoni, D.; Pizzone, R. G.; Signorini, C.; Stefanini, C.; Stroe, L.; Spitaleri, C.

doi:10.1103/PhysRevC.96.044317

States in the astrophysically important Ne-19 nucleus have been populated directly using the O-15(alpha, alpha) O-15 reaction with a radioactive O-15 beam. Due to the challenges involved, this represents the first such O-15 measurement with high resolution and the first dedicated to exploring the cluster structure. This measurement comprises three experiments: the first to develop the O-15 radioactive beam, the second the resonant scattering study, and the third to measure the precise energy loss of O ions in He-4 to reduce systematic uncertainties. The results show evidence for O-15 + alpha cluster structure which could explain earlier results pointing to the increased alpha branching ratio in the astrophysical reaction rate for high-spin near-threshold resonances. Absolute differential cross sections have been measured. Additionally, spins, parities, and partial decay widths, essential for nuclear reaction-rate calculations, have been extracted using an R-matrix analysis.

Evidence for O-15 + alpha resonance structures in Ne-19 via direct measurement / Torresi, D., Wheldon, C., Kokalova, T.z., Bailey, S., Boiano, A., Boiano, C., Fisichella, M., Mazzocco, M., Parascandolo, C., Pierroutsakou, D., Strano, E., Zadro, M., Cavallaro, M., Cherubini, S., Curtis, N., Di Pietro, A., FernÃ¡ndez Garcia, J.P., Figuera, P., Glodariu, T., Grbosz, J., et al.. - In: PHYSICAL REVIEW C. - ISSN 2469-9985. - 96:4(2017), pp. 1-7. [10.1103/PhysRevC.96.044317]