2024/02/26 by Bishop, J., Rogachev, G. V., Ahn, S. +16
#FOS: Physical sciences #Nuclear Experiment (nucl-ex)
paper · doi:10.48550/arxiv.2402.16677
Background: Cluster states in 13N are extremely difficult to measure due to the unavailability of 9B+α elastic scattering data. Purpose: Using β-delayed charged-particle spectroscopy of 13O, clustered states in 13N can be populated and measured in the 3α+p decay channel. Method: One-at-a-time implantation/decay of 13O was performed with the Texas Active Target Time Projection Chamber (TexAT TPC). 149 β3αp decay events were observed and the excitation function in 13N reconstructed. Results: Four previously unknown α-decaying excited states were observed in 13N at an excitation energy of 11.3 MeV, 12.4 MeV, 13.1 MeV and 13.7 MeV decaying via the 3α+p channel. Conclusion: These states are seen to have a [9B(g.s) \bigotimes α/ p+12C(02+)], [9B((1)/(2)+) \bigotimes α], [9B((5)/(2)+) \bigotimes α] and [9B((5)/(2)+) \bigotimes α] structure respectively. A previously-seen state at 11.8 MeV was also determined to have a [p+12C(g.s.)/ p+12C(02+)] structure. The overall magnitude of the clustering is not able to be extracted however due to the lack of a total width measurement. Clustered states in 13N (with unknown magnitude) seem to persist from the addition of a proton to the highly α-clustered 12C. Evidence of the (1)/(2)+ state in 9B was also seen to be populated by decays from 13N⋆.