Shell-structure and pairing interaction in superheavy nuclei; Rotational properties of the =104 nucleus Rf

超重核の殻構造と対相関; 104番元素Rfの回転励起構造

Greenlees, P. T.*; Rubert, J.*; Piot, J.*; Gall, B. J. P.*; Andersson, L. L.*; 浅井 雅人  ; Asfari, Z.*; Cox, D. M.*; Dechery, F.*; Dorvaux, O.*; Grahn, T.*; Hauschild, K.*; Henning, G.*; Herzan, A.*; Herzberg, R.-D.*; Heberger, F. P.*; Jakobsson, U.*; Jones, P.*; Julin, R.*; Juutinen, S.*; Ketelhut, S.*; Khoo, T.-L.*; Leino, M.*; Ljungvall, J.*; Lopez-Martens, A.*; Lozeva, R.*; Nieminen, P.*; Pakarinen, J.*; Papadakis, P.*; Parr, E.*; Peura, P.*; Rahkila, P.*; Rinta-Antila, S.*; Ruotsalainen, P.*; Sandzelius, M.*; Sren, J.*; Scholey, C.*; Seweryniak, D.*; Sorri, J.*; Sulignano, B.*; Theisen, Ch.*; Uusitalo, J.*; Venhart, M.*

Greenlees, P. T.*; Rubert, J.*; Piot, J.*; Gall, B. J. P.*; Andersson, L. L.*; Asai, Masato; Asfari, Z.*; Cox, D. M.*; Dechery, F.*; Dorvaux, O.*; Grahn, T.*; Hauschild, K.*; Henning, G.*; Herzan, A.*; Herzberg, R.-D.*; Heberger, F. P.*; Jakobsson, U.*; Jones, P.*; Julin, R.*; Juutinen, S.*; Ketelhut, S.*; Khoo, T.-L.*; Leino, M.*; Ljungvall, J.*; Lopez-Martens, A.*; Lozeva, R.*; Nieminen, P.*; Pakarinen, J.*; Papadakis, P.*; Parr, E.*; Peura, P.*; Rahkila, P.*; Rinta-Antila, S.*; Ruotsalainen, P.*; Sandzelius, M.*; Sren, J.*; Scholey, C.*; Seweryniak, D.*; Sorri, J.*; Sulignano, B.*; Theisen, Ch.*; Uusitalo, J.*; Venhart, M.*

104番元素Rfの回転励起構造をインビーム線核分光の手法により初めて観測することに成功した。Rfは回転励起構造が観測された最も重い原子核であり、今回の結果は重い極限に位置する原子核の一粒子軌道殻構造と対相関に関する貴重な情報を与える。今回の実験で得られたRfの回転状態の慣性能率の値は、陽子数104における変形閉殻の存在を明確に否定し、近年の数多くの自己無撞着平均場モデルの予測と異なる結果を示した。

Rotational band structure of the =104 nucleus Rf has been observed for the first time using an in-beam -ray spectroscopic technique. This nucleus is the heaviest among the nuclei whose rotational band structure has ever been observed. Thus, the present result provides valuable information on the single-particle shell structure and pairing interaction in the heaviest extreme of nuclei. The deduced moment of inertia indicates that there is no deformed shell gap at =104, which is predicted in a number of current self-consistent mean-field models.