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Marium, M.*; Aoki, Kentaro*; He, Y.*; Yamamoto, Katsuhiro*; Suwansoontorn, A.*; Ikuta, Seiya*; Hara, Mitsuo*; Nagano, Shusaku*; Nagao, Yuki*; Nishikawa, Kei*; et al.
ACS Applied Energy Materials (Internet), 8(22), p.16589 - 16600, 2025/11
Ishigaki, Miho*; Tominaga, Nozomu*; Aoki, Wako*; Wanajo, Shinya*; Takiwaki, Tomoya*; Nakamura, Ko*; Iwamoto, Nobuyuki; Nomoto, Kenichi*; Kobayashi, Chiaki*
Astrophysical Journal, 992(2), p.215_1 - 215_17, 2025/10
-rays emitted from 
S(n,)
S reaction with polarized neutronsEndo, Shunsuke; Fujioka, Hiroyuki*; Ide, Ikuo*; Iinuma, Masataka*; Iwamoto, Nobuyuki; Iwamoto, Osamu; Kameda, Kento*; Kawamura, Shiori*; Kimura, Atsushi; Kitaguchi, Masaaki*; et al.
EPJ Web of Conferences, 329, p.05003_1 - 05003_3, 2025/06
no abstracts in English
Endo, Shunsuke; Abe, Ryota*; Fujioka, Hiroyuki*; Ino, Takashi*; Iwamoto, Osamu; Iwamoto, Nobuyuki; Kawamura, Shiori*; Kimura, Atsushi; Kitaguchi, Masaaki*; Kobayashi, Ryuju*; et al.
European Physical Journal A, 60(8), p.166_1 - 166_10, 2024/08
Times Cited Count：3 Percentile：67.20(Physics, Nuclear)
Linh, B. D.*; Corsi, A.*; Gillibert, A.*; Obertelli, A.*; Doornenbal, P.*; Barbieri, C.*; Duguet, T.*; G
mez-Ramos, M.*; Holt, J. D.*; Hu, B. S.*; et al.
Physical Review C, 109(3), p.034312_1 - 034312_15, 2024/03
Times Cited Count：3 Percentile：67.20(Physics, Nuclear)no abstracts in English
Yoshimura, Nobuyuki*; Toyama, Takeshi*; Shobuda, Yoshihiro; Nakamura, Takeshi*; Omi, Kazuhito*; Kobayashi, Aine*; Okada, Masashi*; Sato, Yoichi*; Nakaya, Tsuyoshi*
Proceedings of 20th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.260 - 264, 2023/11
The J-PARC main ring (MR) will be increased to 1.3 MW. To cope with the increase in beam intensity, the intra-bunch feedback system (IBFB) needs to be upgraded to handle higher frequencies up to about 200 MHz. To evaluate the performance and understand the optimal parameters after this upgrade, we are developing a particle tracking simulation that includes the necessary components. The recoherence period induced by chromaticity between tracking simulations and experiments are compared and it cannot be discribed by the simple simulations, and we investigate what mechanisms explain this result. The shift of synchrotron tune caused by longitudinal wakes using tracking simulations are calculated and it find that introducing the effect of longitudinal wakes only does not explain the recoherence period in the experimental results.
Kido, Eiji*; Inakura, Tsunenori*; Kimura, Masaaki*; Kobayashi, Nobuyuki*; Nagataki, Shigehiro*; Shimizu, Noritaka*; Tamii, Atsushi*; Utsuno, Yutaka
Astroparticle Physics, 152, p.102866_1 - 102866_12, 2023/10
Times Cited Count：3 Percentile：40.74(Astronomy & Astrophysics)no abstracts in English
Tamii, Atsushi*; Pellegri, L.*; S
derstrm, P.-A.*; Allard, D.*; Goriely, S.*; Inakura, Tsunenori*; Khan, E.*; Kido, Eiji*; Kimura, Masaaki*; Litvinova, E.*; et al.
European Physical Journal A, 59(9), p.208_1 - 208_21, 2023/09
Times Cited Count：10 Percentile：90.47(Physics, Nuclear)no abstracts in English
OKondo, Yosuke*; Achouri, N. L.*; Al Falou, H.*; Atar, L.*; Aumann, T.*; Baba, Hidetada*; Boretzky, K.*; Caesar, C.*; Calvet, D.*; Chae, H.*; et al.
Nature, 620(7976), p.965 - 970, 2023/08
Times Cited Count：32 Percentile：95.20(Multidisciplinary Sciences)no abstracts in English
Ca cast doubt on a doubly magic 
CaChen, S.*; Browne, F.*; Doornenbal, P.*; Lee, J.*; Obertelli, A.*; Tsunoda, Yusuke*; Otsuka, Takaharu*; Chazono, Yoshiki*; Hagen, G.*; Holt, J. D.*; et al.
Physics Letters B, 843, p.138025_1 - 138025_7, 2023/08
Times Cited Count：9 Percentile：82.79(Astronomy & Astrophysics)Gamma decays were observed in 
Ca and 
Ca following quasi-free one-proton knockout reactions from 
Sc. For Ca, a ray transition was measured to be 1456(12) keV, while for Ca an indication for a transition was observed at 1115(34) keV. Both transitions were tentatively assigned as the 
decays. A shell-model calculation in a wide model space with a marginally modified effective nucleon-nucleon interaction depicts excellent agreement with experiment for 
level energies, two-neutron separation energies, and reaction cross sections, corroborating the formation of a new nuclear shell above the N = 34 shell. Its constituents, the 
and 
orbitals, are almost degenerate. This degeneracy precludes the possibility for a doubly magic Ca and potentially drives the dripline of Ca isotopes to 
Ca or even beyond.
Ne at the transition into the island of inversion; Detailed structure study of NeWang, H.*; Yasuda, Masahiro*; Kondo, Yosuke*; Nakamura, Takashi*; Tostevin, J. A.*; Ogata, Kazuyuki*; Otsuka, Takaharu*; Poves, A.*; Shimizu, Noritaka*; Yoshida, Kazuki; et al.
Physics Letters B, 843, p.138038_1 - 138038_9, 2023/08
Times Cited Count：5 Percentile：65.61(Astronomy & Astrophysics)Detailed -ray spectroscopy of the exotic neon isotope Ne has been performed using the one-neutron removal reaction from Ne. Based on an analysis of parallel momentum distributions, a level scheme with spin-parity assignments has been constructed for Ne and the negative-parity states are identified for the first time. The measured partial cross sections and momentum distributions reveal a significant intruder p-wave strength providing evidence of the breakdown of the N = 20 and N = 28 shell gaps. Only a weak, possible f-wave strength was observed to bound final states. Large-scale shell-model calculations with different effective interactions do not reproduce the large p-wave and small f-wave strength observed experimentally, indicating an ongoing challenge for a complete theoretical description of the transition into the island of inversion along the Ne isotopic chain.
Ne at the boundary of the island of inversionRevel, A.*; Wu, J.*; Iwasaki, Hironori*; Ash, J.*; Bazin, D.*; Brown, B. A.*; Chen, J.*; Elder, R.*; Farris, P.*; Gade, A.*; et al.
Physics Letters B, 838, p.137704_1 - 137704_7, 2023/03
Times Cited Count：3 Percentile：47.61(Astronomy & Astrophysics)no abstracts in English
Yoshimura, Nobuyuki*; Toyama, Takeshi*; Kobayashi, Aine*; Nakamura, Takeshi*; Okada, Masashi*; Shobuda, Yoshihiro; Nakaya, Tsuyoshi*
Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.936 - 941, 2023/01
no abstracts in English
island of inversion; First study of low-lying bound excited states in 
V and 
VElekes, Z.*; Juh
sz, M. M.*; Sohler, D.*; Sieja, K.*; Yoshida, Kazuki; Ogata, Kazuyuki*; Doornenbal, P.*; Obertelli, A.*; Achouri, N. L.*; Baba, Hidetada*; et al.
Physical Review C, 106(6), p.064321_1 - 064321_10, 2022/12
Times Cited Count：3 Percentile：37.76(Physics, Nuclear)The low-lying level structure of V and V was investigated for the first time. The neutron knockout reaction and inelastic proton scattering were applied for V while the neutron knock-out reaction provided the data for V. Four and five new transitions were determined for V and V, respectively. Based on the comparison to our shell-model calculations using the Lenzi-Nowacki-Poves-Sieja (LNPS) interaction, three of the observed rays for each isotope could be placed in the level scheme and assigned to the decay of the first 11/2
and 9/2 levels. The (
,
) excitation cross sections for V were analyzed by the coupled-channels formalism assuming quadrupole plus hexadecapole deformations. Due to the role of the hexadecapole deformation, V could not be unambiguously placed on the island of inversion.
neutron orbital and the 
shell closure in 
CaEnciu, M.*; Liu, H. N.*; Obertelli, A.*; Doornenbal, P.*; Nowacki, F.*; Ogata, Kazuyuki*; Poves, A.*; Yoshida, Kazuki; Achouri, N. L.*; Baba, Hidetada*; et al.
Physical Review Letters, 129(26), p.262501_1 - 262501_7, 2022/12
Times Cited Count：19 Percentile：84.74(Physics, Multidisciplinary)The one-neutron knockout from Ca was performed at 
230 MeV/nucleon combined with prompt spectroscopy. The momentum distributions corresponding to the removal of 
and 
neutrons were measured. The cross sections are consistent with a shell closure at the neutron number , found as strong as at 
and 
in Ca isotopes from the same observables. The analysis of the momentum distributions leads to a difference of the root-mean-square radii of the neutron 
and orbitals of 0.61(23) fm, in agreement with the modified-shell-model prediction of 0.7 fm suggesting that the large root-mean-square radius of the orbital in neutron-rich Ca isotopes is responsible for the unexpected linear increase of the charge radius with the neutron number.
Ca; Spectroscopy of 
K, Ca, and 
CaKoiwai, Takuma*; Wimmer, K.*; Doornenbal, P.*; Obertelli, A.*; Barbieri, C.*; Duguet, T.*; Holt, J. D.*; Miyagi, Takayuki*; Navrtil, P.*; Ogata, Kazuyuki*; et al.
Physics Letters B, 827, p.136953_1 - 136953_7, 2022/04
Times Cited Count：8 Percentile：69.44(Astronomy & Astrophysics)no abstracts in English
Cl isotopesLinh, B. D.*; Corsi, A.*; Gillibert, A.*; Obertelli, A.*; Doornenbal, P.*; Barbieri, C.*; Chen, S.*; Chung, L. X.*; Duguet, T.*; Gmez-Ramos, M.*; et al.
Physical Review C, 104(4), p.044331_1 - 044331_16, 2021/10
Times Cited Count：11 Percentile：73.35(Physics, Nuclear)no abstracts in English
Ca from direct reactionsBrowne, F.*; Chen, S.*; Doornenbal, P.*; Obertelli, A.*; Ogata, Kazuyuki*; Utsuno, Yutaka; Yoshida, Kazuki; Achouri, N. L.*; Baba, Hidetada*; Calvet, D.*; et al.
Physical Review Letters, 126(25), p.252501_1 - 252501_7, 2021/06
Times Cited Count：12 Percentile：65.78(Physics, Multidisciplinary)Direct proton-knockout reactions of Sc were studied at the RIKEN Radioactive Isotope Beam Factory. Populated states of Ca were investigated through -ray and invariant-mass spectroscopy. Level energies were calculated from the nuclear shell model employing a phenomenological inter-nucleon interaction. Theoretical cross sections to states were calculated from distorted-wave impulse approximation estimates multiplied by the shell model spectroscopic factors. Despite the calculations showing a significant amplitude of excited neutron configurations in the ground-state of Sc, valence proton removals populated predominantly the ground-state of Ca. This counter-intuitive result is attributed to pairing effects leading to a dominance of the ground-state spectroscopic factor. Owing to the ubiquity of the pairing interaction, this argument should be generally applicable to direct knockout reactions from odd-even to even-even nuclei.
Ar by the (,2) reactionJuhsz, M. M.*; Elekes, Z.*; Sohler, D.*; Utsuno, Yutaka; Yoshida, Kazuki; Otsuka, Takaharu*; Ogata, Kazuyuki*; Doornenbal, P.*; Obertelli, A.*; Baba, Hidetada*; et al.
Physics Letters B, 814, p.136108_1 - 136108_8, 2021/03
Times Cited Count：7 Percentile：58.67(Astronomy & Astrophysics)The nuclear structure of Ar was studied by the (,2) reaction using -ray spectroscopy for the bound and unbound states. Comparing the results to our shell-model calculations, two bound and six unbound states were established. The low cross sections populating the two bound states of Ar could be interpreted as a clear signature for the presence of significant sub-shell closures at neutron numbers 32 and 34 in argon isotopes.
clusters in dilute neutron-rich matterTanaka, Junki*; Yang, Z.*; Typel, S.*; Adachi, Satoshi*; Bai, S.*; van Beek, P.*; Beaumel, D.*; Fujikawa, Yuki*; Han, J.*; Heil, S.*; et al.
Science, 371(6526), p.260 - 264, 2021/01
Times Cited Count：81 Percentile：99.34(Multidisciplinary Sciences)By employing quasi-free -cluster-knockout reactions, we obtained direct experimental evidence for the formation of clusters at the surface of neutron-rich tin isotopes. The observed monotonous decrease of the reaction cross sections with increasing mass number, in excellent agreement with the theoretical prediction, implies a tight interplay between -cluster formation and the neutron skin.
