학술논문
Extending the Southern Shore of the Island of Inversion to F28
Document Type
article
Author
Revel, A; Sorlin, O; Marqués, FM; Kondo, Y; Kahlbow, J; Nakamura, T; Orr, NA; Nowacki, F; Tostevin, JA; Yuan, CX; Achouri, NL; Al Falou, H; Atar, L; Aumann, T; Baba, H; Boretzky, K; Caesar, C; Calvet, D; Chae, H; Chiga, N; Corsi, A; Crawford, HL; Delaunay, F; Delbart, A; Deshayes, Q; Dombrádi, Z; Douma, CA; Elekes, Z; Fallon, P; Gašparić, I; Gheller, J-M; Gibelin, J; Gillibert, A; Harakeh, MN; He, W; Hirayama, A; Hoffman, CR; Holl, M; Horvat, A; Horváth, Á; Hwang, JW; Isobe, T; Kalantar-Nayestanaki, N; Kawase, S; Kim, S; Kisamori, K; Kobayashi, T; Körper, D; Koyama, S; Kuti, I; Lapoux, V; Lindberg, S; Masuoka, S; Mayer, J; Miki, K; Murakami, T; Najafi, M; Nakano, K; Nakatsuka, N; Nilsson, T; Obertelli, A; de Oliveira Santos, F; Otsu, H; Ozaki, T; Panin, V; Paschalis, S; Rossi, D; Saito, AT; Saito, T; Sasano, M; Sato, H; Satou, Y; Scheit, H; Schindler, F; Schrock, P; Shikata, M; Shimizu, Y; Simon, H; Sohler, D; Stuhl, L; Takeuchi, S; Tanaka, M; Thoennessen, M; Törnqvist, H; Togano, Y; Tomai, T; Tscheuschner, J; Tsubota, J; Uesaka, T; Yang, Z; Yasuda, M; Yoneda, K
Source
Physical Review Letters. 124(15)
Subject
Language
Abstract
Detailed spectroscopy of the neutron-unbound nucleus ^{28}F has been performed for the first time following proton/neutron removal from ^{29}Ne/^{29}F beams at energies around 230 MeV/nucleon. The invariant-mass spectra were reconstructed for both the ^{27}F^{(*)}+n and ^{26}F^{(*)}+2n coincidences and revealed a series of well-defined resonances. A near-threshold state was observed in both reactions and is identified as the ^{28}F ground state, with S_{n}(^{28}F)=-199(6) keV, while analysis of the 2n decay channel allowed a considerably improved S_{n}(^{27}F)=1620(60) keV to be deduced. Comparison with shell-model predictions and eikonal-model reaction calculations have allowed spin-parity assignments to be proposed for some of the lower-lying levels of ^{28}F. Importantly, in the case of the ground state, the reconstructed ^{27}F+n momentum distribution following neutron removal from ^{29}F indicates that it arises mainly from the 1p_{3/2} neutron intruder configuration. This demonstrates that the island of inversion around N=20 includes ^{28}F, and most probably ^{29}F, and suggests that ^{28}O is not doubly magic.