Cluster structure of 3α+p states in N13

Abstract

Cluster states in N13 are extremely difficult to measure due to the unavailability of B9+α elastic-scattering data. Using β-delayed charged-particle spectroscopy of O13, clustered states in N13 can be populated and measured in the 3α+p decay channel. One-at-a-time implantation and decay of O13 was performed with the Texas Active Target Time Projection Chamber. 149β3αp decay events were observed and the excitation function in N13 reconstructed. Four previously unknown α-decaying excited states were observed in N13 at an excitation energy of 11.3, 12.4, 13.1, and 13.7 MeV decaying via the 3α+p channel. These states are seen to have a [9B(g.s)⨂α/p+C12(02+)], [9B(12+)⨂α], [9B(52+)⨂α], and [9B(52+)⨂α] structure, respectively. A previously seen state at 11.8 MeV was also determined to have a [p+C12(g.s.)/p+C12(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 N13 (with unknown magnitude) seem to persist from the addition of a proton to the highly α-clustered C12. Evidence of the 12+ state in B9 was also seen to be populated by decays from N★13.Published by the American Physical Society2024