Cluster structure of 3$\hat{I}\pm$+p states in ${}^{13}$N

Abstract

Background: Cluster states in ${}^{13}$N are extremely difficult to measure due to the unavailability of ${}^9$B+$\hat{I}\pm$ elastic scattering data. Purpose: Using ${\hat{I}}^2$-delayed charged-particle spectroscopy of ${}^{13}$O, clustered states in ${}^{13}$N can be populated and measured in the 3$\hat{I}\pm$+p decay channel. Method: One-at-a-time implantation/decay of ${}^{13}$O was performed with the Texas Active Target Time Projection Chamber (TexAT TPC). 149 ${\hat{I}}^{2}3\hat{I}\pm p$ decay events were observed and the excitation function in ${}^{13}$N reconstructed. Results: Four previously unknown $\hat{I}\pm$-decaying excited states were observed in ${}^{13}$N at an excitation energy of 11.3 MeV, 12.4 MeV, 13.1 MeV and 13.7 MeV decaying via the 3$\hat{I}\pm$+p channel. Conclusion: These states are seen to have a [${}^9\mathrm{B}(g.s)⨂\hat{I}\pm$/ $p{+}^{12}\mathrm{C}(0_2^{+})$], [${}^9\mathrm{B}({\frac{1}{2}}^{+})⨂\hat{I}\pm$], [${}^9\mathrm{B}({\frac{5}{2}}^{+})⨂\hat{I}\pm$] and [${}^9\mathrm{B}({\frac{5}{2}}^{+})⨂\hat{I}\pm$] structure respectively. A previously-seen state at 11.8 MeV was also determined to have a [$p{+}^{12}\mathrm{C}(g.s.)$/ $p{+}^{12}\mathrm{C}(0_2^{+})$] 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 ${}^{13}$N (with unknown magnitude) seem to persist from the addition of a proton to the highly $\hat{I}\pm$-clustered ${}^{12}$C. Evidence of the ${\frac{1}{2}}^{+}$ state in ${}^9$B was also seen to be populated by decays from ${}^{13}$N${}^{\star }$.

arXiv admin note: substantial text overlap with arXiv:2302.14111