학술논문
Quasi-free Neutron Knockout Reaction Reveals a Small $s$-orbital Component in the Borromean Nucleus $^{17}$B
Document Type
Working Paper
Author
Yang, Z. H.; Kubota, Y.; Corsi, A.; Yoshida, K.; Sun, X. -X.; Li, J. G.; Kimura, M.; Michel, N.; Ogata, K.; Yuan, C. X.; Yuan, Q.; Authelet, G.; Baba, H.; Caesar, C.; Calvet, D.; Delbart, A.; Dozono, M.; Feng, J.; Flavigny, F.; Gheller, J. -M.; Gibelin, J.; Giganon, A.; Gillibert, A.; Hasegawa, K.; Isobe, T.; Kanaya, Y.; Kawakami, S.; Kim, D.; Kiyokawa, Y.; Kobayashi, M.; Kobayashi, N.; Kobayashi, T.; Kondo, Y.; Korkulu, Z.; Koyama, S.; Lapoux, V.; Maeda, Y.; Marqes, F. M.; Motobayashi, T.; Miyazaki, T.; Nakamura, T.; Nakatsuka, N.; Nishio, Y.; Obertelli, A.; Ohkura, y A.; Orr, N. A.; Ota, S.; Otsu, H.; Ozaki, T.; Panin, V.; Paschalis, S.; Pollacco, E. C.; Reichert, S.; Rousse, J. -Y.; Saito, A. T.; Sakaguchi, S.; Sako, M.; Santamaria, C.; Sasano, 4 M.; Sato, H.; Shikata, M.; Shimizu, Y.; Shindo, Y.; Stuhl, L.; Sumikama, T.; Sun, Y. L.; Tabata, M.; Togano, Y.; Tsubota, J.; Xu, F. R.; Yasuda, J.; Yoneda, K.; Zenihiro, J.; Zhou, S. -G.; Zuo, W.; Uesaka, T.
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Subject
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Abstract
A kinematically complete quasi-free $(p,pn)$ experiment in inverse kinematics was performed to study the structure of the Borromean nucleus $^{17}$B, which had long been considered to have neutron halo. By analyzing the momentum distributions and exclusive cross sections, we obtained the spectroscopic factors for $1s_{1/2}$ and $0d_{5/2}$ orbitals, and a surprisingly small percentage of 9(2)$\%$ was determined for $1s_{1/2}$. Our finding of such a small $1s_{1/2}$ component and the halo features reported in prior experiments can be explained by the deformed relativistic Hartree-Bogoliubov theory in continuum, revealing a definite but not dominant neutron halo in $^{17}$B. The present work gives the smallest $s$- or $p$-orbital component among known nuclei exhibiting halo features, and implies that the dominant occupation of $s$ or $p$ orbitals is not a prerequisite for the occurrence of neutron halo.
Comment: Accepted for publication in Physical Review Letters,8 pages, 4 figures
Comment: Accepted for publication in Physical Review Letters,8 pages, 4 figures