New γ -ray transitions observed in Ne 19 with implications for the O 15 (α,γ) Ne 19 reaction rate
The O15(α,γ)Ne19 reaction is responsible for breakout from the hot CNO cycle in type I x-ray bursts. Understanding the properties of resonances between Ex=4 and 5 MeV in Ne19 is crucial in the calculation of this reaction rate. The spins and parities of these states are well known, with the exception of the 4.14- and 4.20-MeV states, which have adopted spin-parities of 9/2- and 7/2-, respectively. γ-ray transitions from these states were studied using triton-γ-γ coincidences from the F19(He3,tγ)Ne19 reaction measured with the GODDESS (Gammasphere ORRUBA Dual Detectors for Experimental Structure Studies) at Argonne National Laboratory. The observed transitions from the 4.14- and 4.20-MeV states provide strong evidence that the Jπ values are actually 7/2- and 9/2-, respectively. These assignments are consistent with the values in the F19 mirror nucleus and in contrast to previously accepted assignments.
Publication Source (Journal or Book title)
Physical Review C
Hall, M., Bardayan, D., Baugher, T., Lepailleur, A., Pain, S., Ratkiewicz, A., Ahn, S., Allen, J., Anderson, J., Ayangeakaa, A., Blackmon, J., Burcher, S., Carpenter, M., Cha, S., Chae, K., Chipps, K., Cizewski, J., Febbraro, M., Hall, O., Hu, J., Jiang, C., Jones, K., Lee, E., O'Malley, P., Ota, S., Rasco, B., Santiago-Gonzalez, D., Seweryniak, D., Sims, H., Smith, K., Tan, W., Thompson, P., & Thornsberry, C. (2019). New γ -ray transitions observed in Ne 19 with implications for the O 15 (α,γ) Ne 19 reaction rate. Physical Review C, 99 (3) https://doi.org/10.1103/PhysRevC.99.035805