The 18th CNS International Summer School (CNSSS19)

Search for α clustering in 14O

Not scheduled

15m

Wako/Hongo Campus

poster presentation Poster Session by Young Scientists

Speaker

Shintaro Okamoto (Dept. of Phys., Kyoto Univ.)

Description

$\alpha$ clustering is a well-known phenomenon in light nuclei where two neutrons and two protons strongly correlate to constitute an $\alpha$ particle as a building block of atomic nuclei. A linear alignment of the $\alpha$ clusters, referred to as linear-chain cluster state (LCCS), has been of great interest since 1950s but until now there is no clear experimental evidence demonstrating the existence of such a state. Recently, it was theoretically pointed out that excess nucleons in non-4N nuclei occupy molecular orbitals between $\alpha$ clusters and the excess nucleons may stabilize LCCS. A candidate of LCCS in ${}^{14}$C was experimentally proposed by H. Yamaguchi et al. [1].

It is an interesting issue whether the similar LCCS also exists in the mirror nucleus ${}^{14}$O or not. The excess neutrons are replaced by protons in this case, and thus the energy shifts between ${}^{14}$C and ${}^{14}$O due to the Coulomb force should reflect spatial distribution of the excess nucleons. Therefore, it is expected to reveal the structure of the LCCS candidate by measuring its energy in ${}^{14}$O and comparing it with that in ${}^{14}$C and theoretical calculation.

Since ${}^{14}$O is an unstable nucleus, it must be generated as a secondary particle. We conducted the experiment to search for $\alpha$ cluster states in ${}^{14}$O at CRIB facility of CNS, the Univ. of Tokyo in June 2019. In this experiment, we injected a ${}^{10}$C secondary beam at 36 MeV into the He gas target at 650 Torr, and measured the resonant elastic scattering of $\alpha$+${}^{10}$C with the Si detectors at 0 and $\pm$9 degrees by the thick target method. We will report details of the experiment and results in the talk.

References
[1] H. Yamaguchi et. al. Experimental investigation of a linear-chain structure in the nucleus ${}^{14}$C $Phys.Lett.B,$ 766:11, 2017