Investigation of spatial manifestation of $\alpha$ clusters in ${}^{16}$O via $\alpha$-transfer reactions

Abstract

Recently, we have determined surface distributions of $\alpha$ clusters in the ground state of ${}^{20}\mathrm{Ne}$ from $\alpha$-transfer cross sections, without investigating the properties of its excited states. In this paper we extend our comprehension of $\alpha$-cluster structures in excited states of nuclei through reaction studies. In particular we focus on ${}^{16}\mathrm{O}$, for which attention has been paid to advances of structure theory and assignment regarding $4^{+}$-resonance states. We study the surface manifestation of the $\alpha$-cluster states in both the ground and excited states of ${}^{16}\mathrm{O}$ from the analysis of the $\alpha$-transfer reaction ${}^{12}\mathrm{C}{(}^6\mathrm{Li},d{)}^{16}\mathrm{O}$. The $\alpha$-transfer reaction is described by the distorted-wave Born approximation. We test two microscopic wave functions as an input of reaction calculations. Then a phenomenological potential model is introduced to clarify the correspondence between cluster-wave functions and transfer-cross sections. Surface peaks of the $\alpha$-wave function of ${}^{16}\mathrm{O}(0^{+})$ are sensitively probed by transfer-cross sections at forward angles, while it remains unclear how we trace the surface behavior of ${}^{16}\mathrm{O}(4^{+})$ from the cross sections. We are able to specify that the $\alpha$-cluster structure in the $0_1^{+}$ and $0_2^{+}$ states prominently manifests itself at the radii $\sim 4$ and $\sim 4.5$~fm, respectively. It is remarkable that the $4_1^{+}$ state has the ${}^{12}\mathrm{C}+\alpha$-cluster component with the surface peak at the radius $\sim 4$ or outer, whereas the ${}^{12}\mathrm{C}+\alpha$-cluster component in the $4_2^{+}$ state is found not to be dominant. The $4_2^{+}$ state is difficult to be interpreted by a simple potential model assuming the ${}^{12}\mathrm{C}+\alpha$ configuration only.

arXiv comment14 pages, 7 figures

References in corpus (16)

• Alpha-particle condensation in 16O via a full four-body OCM calculation
• Ab initio calculation of the spectrum and structure of ${}^{16}$O
• Evidence for tetrahedral symmetry in 16O
• Isoscalar monopole excitations in ${}^{16}$O: $\alpha$-cluster states at low energy and mean-field-type states at higher energy
• The Algebraic Cluster Model: Structure of 16O
• Microscopic study of 4-alpha-particle condensation with proper treatment of resonances
• Investigating the alpha-clustering on the surface of ${}^{120}$Sn via ($p$,$p\alpha$) reaction and the validity of the factorization approximation
• Cluster states and monopole transitions in ${}^{16}$O
• Manifestation of α-clustering in ${}^{10}$Be via α-knockout reaction
• Correlated-basis description of $\alpha$-cluster and delocalized $0^{+}$ states in ${}^{16}$O
• Investigation of $\alpha$ clustering with knockout reactions
• Tetrahedral $4\alpha$ and ${}^{12}\text{C}+\alpha$ cluster structures in ${}^{16}$O
• Probing surface distributions of $\alpha$ clusters in ${}^{20}$Ne via $\alpha$-transfer reaction
• Breakup and finite-range effects on the 8B(d,n)9C reaction
• Three-Body Model Analysis of Subbarrier alpha Transfer Reaction
• alpha-cluster correlations and symmetry breaking in light nuclei

Cited by in corpus (3)

• Oxygen-16 Spectrum from Tetrahedral Vibrations and their Rotational Excitations
• $\alpha$ and triton clustering in ${}^{35}$Cl
• Semi-microscopic construction of multi-$\alpha$ cluster spaces