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First observation of 28O

Kondo, Y.; Achouri, N. L.; Falou, H. Al; Atar, L.; Aumann, T.; Baba, H.; Boretzky, K.; Caesar, C.; Calvet, D.; Chae, H.; Chiga, N.; Corsi, A.; Delaunay, F.; Delbart, A.; Deshayes, Q.; Dombrádi, Zs.; Douma, C. A.; Ekström, A.; Elekes, Z.; Forssén, C.; Gašparić, I.; Gheller, J.-M.; Gibelin, J.; Gillibert, A.; Hagen, G.; Harakeh, M. N.; Hirayama, A.; Hoffman, C. R.; Holl, M.; Horvat, A.; Horváth, Á.; Hwang, J. W.; Isobe, T.; Jiang, W. G.; Kahlbow, J.; Kalantar-Nayestanaki, N.; Kawase, S.; Kim, S.; Kisamori, K.; Kobayashi, T.; Körper, D.; Koyama, S.; Kuti, I.; Lapoux, V.; Lindberg, S.; Marqués, F. M.; Masuoka, S.; Mayer, J.; Miki, K.; Murakami, T.; Najafi, M.; Nakamura, T.; Nakano, K.; Nakatsuka, N.; Nilsson, T.; Obertelli, A.; Ogata, K.; de Oliveira Santos, F.; Orr, N. A.; Otsu, H.; Otsuka, T.; Ozaki, T.; Panin, V.; Papenbrock, T.; Paschalis, S.; Revel, A.; Rossi, D.; Saito, A. T.; Saito, T. Y.; Sasano, M.; Sato, H.; Satou, Y.; Scheit, H.; Schindler, F.; Schrock, P.; Shikata, M.; Shimizu,...

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Y. Kondo

N. L. Achouri

H. Al Falou

L. Atar

T. Aumann

H. Baba

K. Boretzky

C. Caesar

D. Calvet

H. Chae

N. Chiga

A. Corsi

F. Delaunay

A. Delbart

Q. Deshayes

Zs. Dombrádi

C. A. Douma

A. Ekström

Z. Elekes

C. Forssén

I. Gašparić

J.-M. Gheller

J. Gibelin

A. Gillibert

G. Hagen

M. N. Harakeh

A. Hirayama

C. R. Hoffman

M. Holl

A. Horvat

Á. Horváth

J. W. Hwang

T. Isobe

W. G. Jiang

J. Kahlbow

N. Kalantar-Nayestanaki

S. Kawase

S. Kim

K. Kisamori

T. Kobayashi

D. Körper

S. Koyama

I. Kuti

V. Lapoux

S. Lindberg

F. M. Marqués

S. Masuoka

J. Mayer

K. Miki

T. Murakami

M. Najafi

T. Nakamura

K. Nakano

N. Nakatsuka

T. Nilsson

A. Obertelli

K. Ogata

F. de Oliveira Santos

N. A. Orr

H. Otsu

T. Otsuka

T. Ozaki

V. Panin

T. Papenbrock

S. Paschalis

A. Revel

D. Rossi

A. T. Saito

T. Y. Saito

M. Sasano

H. Sato

Y. Satou

H. Scheit

F. Schindler

P. Schrock

M. Shikata

N. Shimizu

Y. Shimizu

H. Simon

D. Sohler

O. Sorlin

L. Stuhl

Z. H. Sun

S. Takeuchi

M. Tanaka

M. Thoennessen

H. Törnqvist

Y. Togano

T. Tomai

J. Tscheuschner

J. Tsubota

N. Tsunoda

T. Uesaka

Y. Utsuno

H. Wang

Z. Yang

M. Yasuda

K. Yoneda

S. Yoshida


Subjecting a physical system to extreme conditions is one of the means often used to obtain a better understanding and deeper insight into its organization and structure. In the case of the atomic nucleus, one such approach is to investigate isotopes that have very different neutron-to-proton (N/Z) ratios than in stable nuclei. Light, neutron-rich isotopes exhibit the most asymmetric N/Z ratios and those lying beyond the limits of binding, which undergo spontaneous neutron emission and exist only as very short-lived resonances (about 10−21 s), provide the most stringent tests of modern nuclear-structure theories. Here we report on the first observation of 28O and 27O through their decay into 24O and four and three neutrons, respectively. The 28O nucleus is of particular interest as, with the Z = 8 and N = 20 magic numbers1,2, it is expected in the standard shell-model picture of nuclear structure to be one of a relatively small number of so-called ‘doubly magic’ nuclei. Both 27O and 28O were found to exist as narrow, low-lying resonances and their decay energies are compared here to the results of sophisticated theoretical modelling, including a large-scale shell-model calculation and a newly developed statistical approach. In both cases, the underlying nuclear interactions were derived from effective field theories of quantum chromodynamics. Finally, it is shown that the cross-section for the production of 28O from a 29F beam is consistent with it not exhibiting a closed N = 20 shell structure.


Kondo, Y., Achouri, N. L., Falou, H. A., Atar, L., Aumann, T., Baba, H., …Yoshida, S. (2023). First observation of 28O. Nature, 620(7976), 965-970.

Journal Article Type Article
Acceptance Date Jun 21, 2023
Online Publication Date Aug 30, 2023
Publication Date Aug 31, 2023
Deposit Date Sep 4, 2023
Publicly Available Date Nov 13, 2023
Journal Nature
Print ISSN 0028-0836
Electronic ISSN 1476-4687
Publisher Nature Research
Peer Reviewed Peer Reviewed
Volume 620
Issue 7976
Pages 965-970
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Published Journal Article (4.7 Mb)


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