強い相互作用で探る原子核中の弱い相互作用による遷移

2014 Fiscal Year Annual Research Report

• Project/Area Number: 22540310
• Research Institution: Osaka University
• Principal Investigator: 藤田 佳孝 大阪大学, 核物理研究センター, 准教授 (60093457)
• Co-Investigator(Kenkyū-buntansha): 民井 淳 大阪大学, 核物理研究センター, 准教授 (20302804)
• Project Period (FY): 2010-04-01 – 2015-03-31
• Keywords: ガモフテラー遷移 / 荷電交換反応 / ベータ崩壊 / 高分解能(3He,t)反応 / 荷電スピン / 鏡映核 / 弱い相互作用 / 国際研究者交流・スペイン・アメリカ・トルコ

Outline of Annual Research Achievements

宇宙でのミクロで動的な元素合成に目を向けると、弱い相互作用の働き、特に原子核でのガモフテラー(GT)遷移の寄与が大きい。超新星爆発等に伴う高温高密度状態でのニュートリノ起源の元素合成はその典型例である。ベータ崩壊の研究では、半減期から GT遷移強度の絶対値が決まるが、高励起状態への遷移を研究できない。
そこで強い相互作用で起こる (3He,t)荷電交換反応が逆ベータ崩壊のように振る舞い、しかも高励起状態への遷移の研究が可能であることに目をつけた。弱い相互作用で起こるGT遷移の詳細を、ベータ崩壊の研究と比較しながら、強い相互作用で起こる高分解能荷電交換反応を用い研究する。原子核・GT遷移の全体像を理解しようとしている。
sd-殻核とpf-殻核にまたがる構造を持つ、40Arから40Kへの(3He,t)反応で調べた GT遷移の強度に、鏡映で相補関係にあるベータ崩壊の研究結果とで、20％程度とかなり大きな不一致が見られた。殻モデル計算を参照し、これらの不一致は、sd-殻とpf-殻の波動関数の干渉で説明できる事がわかった (Phys. Rev. C 誌)。
フランス・GANIL研究所でのpf-殻核 56Zn-->56Cuのベータ崩壊を陽子崩壊を通して調べた。その結果と鏡映関係にある 56Fe(3He,t)56Co反応の結果で大幅な不一致が見られた。56Cuのガンマー崩壊の結果も含めた解析で、新しいベータ崩壊のモード"delayed-gamma-proton decay"の存在に由来する事がわかった (Phys. Rev. Let. 誌)。
A=42-54の4種類の荷電スピン T=1 のpf-殻核からのベータ崩壊の結果と、鏡映関係にある(3He,t)反応の結果を丁寧に比較した。個々のGT遷移は少しばらつくが、全体としてきれいな対称性が見られた (Phys. Rev. C 誌)。

Research Progress Status

26年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

26年度が最終年度であるため、記入しない。

Research Products

• [Journal Article] Tz = -1 → 0 β decays of 54Ni, 50Fe, 46Cr, and 42Ti and comparison with mirror (3He,t) measurements (2015)
  • Author(s): F. Molina, B. Rubio, Y. Fujita, W. Gelletly, J. Agramunt, A. Algora, J. Benlliure, E. Casarejos, H. Geissel, J. Gerl, I. Kojouharov, H. Matsubara, A.I. Morales, Y. Oktem, D. Pauwels, D. P´erez-Loureiro, S. Pietri, Zs. Podoly´ak, W. Prokopowicz, D. Rudolph, H. Schaffner, S.J. Steer, J.L. Tain, A. Tamii et al.
  • Journal Title: PHYSICAL REVIEW C Volume: 91 Pages: 014301 1-19
  • DOI: 10.1103/PhysRevC.91.014301
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Observation of Muonic X-rays of Cosmic-Ray Muons Stopped in Al and Fe Targets (2015)
  • Author(s): Yoshihiro Shimbara, Teiichiro Matsuzaki, Kosuke Abe, Yoshitaka Fujita, Jun Goto, Takeshi Itoh, Naoki Kikukawa, Masayuki Nagashima, Yoshihiro Nakamura, Toshiyuki Ogura, Takashi Ohtsubo, Susumu Ohya, Taku Sakai, Daishiro Sera, Shinji Suzuki, Kosumo Takeda, Azumi Yajima, and Takenori Yoshikawa
  • Journal Title: Journal of the Physical Society of Japan Volume: 84 Pages: 034301 1-5
  • DOI: 10.7566/JPSJ.84.034301
  • Peer Reviewed
• [Journal Article] Low-energy electric dipole response in 120Sn (2015)
  • Author(s): A.M. Krumbholz, P. von Neumann-Cosel, T. Hashimoto, A. Tamii, T. Adachi, C.A. Bertulani, H. Fujita, Y. Fujita, E. Ganioglu, K. Hatanaka, C. Iwamoto, T. Kawabata, N.T. Khai, A. Krugmann, D. Martin, H. Matsubara, R. Neveling, H. Okamura, H.J. Ong, I. Poltoratska et al.
  • Journal Title: Physics Letters B Volume: 744 Pages: 7-12
  • DOI: 10.1016/j.physletb.2015.03.023
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Precision evaluation of the 71Ga(νe,e') solar neutrino capture rate from the (3He,t) charge-exchange reaction (2015)
  • Author(s): D. Frekers, T. Adachi, H. Akimune, M. Alanssari, B.A. Brown, B.T. Cleveland, H. Ejiri, H. Fujita, Y. Fujita, M. Fujiwara, V.N. Gavrin, M.N. Harakeh, K. Hatanaka, M. Holl, C. Iwamoto, A. Lennarz, A. Okamoto, H. Okamura, T. Suzuki, and A. Tamii
  • Journal Title: PHYSICAL REVIEW C Volume: 91 Pages: 034608 1-7
  • DOI: 10.1103/PhysRevC.91.034608
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Gamow-Teller transitions in the A = 40 isoquintet of relevance for neutrino captures in 40Ar (2014)
  • Author(s): M. Karakoc, R.G.T. Zegers, B.A. Brown, Y. Fujita, T. Adachi, I. Boztosun, H. Fujita, M. Csatl´os, J.M. Deaven, C.J. Guess, J. Guly´as, K. Hatanaka, K. Hirota, D. Ishikawa, A. Krasznahorkay, H. Matsubara, R. Meharchand, F. Molina, et al.
  • Journal Title: PHYSICAL REVIEW C Volume: ８９ Pages: 064313 1-7
  • DOI: 10.1103/PhysRevC.89.064313
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Observation of the β-Delayed γ-Proton Decay of 56Zn and its Impact on the Gamow-Teller Strength Evaluation (2014)
  • Author(s): S.E.A. Orrigo, B. Rubio, Y. Fujita, B. Blank, W. Gelletly, J. Agramunt, A. Algora, P. Ascher, B. Bilgier, L. C´aceres, R.B. Cakirli, H. Fujita, E. Ganioglu, M. Gerbaux, J. Giovinazzo, S. Gr´evy, O. Kamalou, H.C. Kozer, L. Kucuk, T. Kurtukian-Nieto, F. Molina, L. Popescu et al.
  • Journal Title: PHYSICAL REVIEW LETTERS Volume: 112 Pages: 222501 1-5
  • DOI: 10.1103/PhysRevLett.112.222501
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Half-Life Systematics across the N=126 Shell Closure: Role of First-Forbidden Transitions in the β Decay of Heavy Neutron-Rich Nuclei (2014)
  • Author(s): A.I. Morales, J. Benlliure, T. Kurtukian-Nieto, K.-H Schmidt, E. Casarejos, N. Al-Dahan, A. Algora, N. Alkhomashi, H. ´Alvarez-Pol, G. Benzoni, A. Blazhev, P. Boutachkov, A.M. Bruce, Y. Fujita, A.B. Garnsworthy, W. Gelletly, F. Molina, D. Mucher, B. Rubio, H. Shaffner, S.J. Steer, A. Tamii et al.
  • Journal Title: PHYSICAL REVIEW LETTERS Volume: 113 Pages: 022702 1-5
  • DOI: 10.1103/PhysRevLett.113.022702
  • Peer Reviewed
• [Journal Article] Gamow-Teller transition strengths from 56Fe extracted from the 56Fe(t,3He) reaction (2014)
  • Author(s): M. Scott, Y. Shimbara, Sam M. Austin, D. Bazin, B.A. Brown, J.M. Deaven, Y. Fujita, C.J. Guess, S. Gupta, G.W. Hitt, D. Koeppe, R. Meharchand, M. Nagashima, G. Perdikakis, A. Prinke, M. Sasano, C. Sullivan, L. Valdez, and R.G.T. Zegers
  • Journal Title: PHYSICAL REVIEW C Volume: 90 Pages: 025801 1-8
  • DOI: 10.1103/PhysRevC.90.025801
  • Peer Reviewed
• [Journal Article] Low-energy collective Gamow-Teller states and isoscalar pairing interaction (2014)
  • Author(s): C.L. Bai, H. Sagawa, G. Col`o, Y. Fujita, H.Q. Zhang, X.Z. Zhang, and F.R. Xu
  • Journal Title: PHYSICAL REVIEW C Volume: 90 Pages: 054335 1-12
  • DOI: 10.1103/PhysRevC.90.054335
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Beta Decay Study of the Tz = -2 56Zn Nucleus and the Determination of the Half-Lives of a Few fp-shell Nuclei (2014)
  • Author(s): B. Rubio, S.E.A. Orrigo, L. Kucuk, A. Montaner-Piz`a, Y. Fujita, H. Fujita, B. Blank, W. Gelletly, T. Adachi, P. Ascher, L. C´aceres, G. de France, J. Giovinazzo, S. Gr´evy, H.C. Kozer, F.M. Marqu´es, F. Molina, L. Popescu, R. Raabe, G. Susoy, C. Stodel, T. Suzuki, A. Tamii, and J.C. Thomas et al.
  • Journal Title: Nuclear Data Sheets Volume: 120 Pages: 37-40
  • DOI: 10.1016/j.nds.2014.06.135
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Beta decay of exotic Tz = -1, -2 nuclei: the interesting case of 56Zn (2014)
  • Author(s): S.E.A. Orrigo, B. Rubio, Y. Fujita, B. Blank, W. Gelletly, J. Agramunt, A. Algora, P. Ascher, H. Fujita, E. Ganioglu, M. Gerbaux, J. Giovinazzo, T. Kurtukian-Nieto, F. Molina, L. Popescu, G. Susoy, C. Stodel, T. Suzuki, A. Tamii et al.
  • Journal Title: EPJ Web of Conferences Volume: 66 Pages: 02077 1-4
  • DOI: 10.1051/epjconf/20146602077
  • Open Access / Acknowledgement Compliant
• [Journal Article] Pygmy Dipole Resonance and Dipole Polarizability in 90Zr (2014)
  • Author(s): C. Iwamoto, A. Tamii, H. Utsunomiya, H. Akimune, H. Nakada, T. Shima, T. Hashimoto, T. Yamagata, T. Kawabata, Y. Fujita, H. Matsubara, T. Suzuki, H. Fujita, Y. Shimbara, M. Nagashima, M. Sakuda, T. Mori, T. Izumi, A. Okamoto, T. Kondo, T.-W. Lui, B. Bilgier, H. C. Kozer, and K. Hatanaka
  • Journal Title: AIP Conference Proceedings Volume: 1594 Pages: 426-431
  • DOI: 10.1063/1.4874105
• [Journal Article] Beta decay of the exotic Tz = 2, 56Zn nucleus and half-life of various proton-rich Tz = 1 nuclei (2014)
  • Author(s): S.E.A. Orrigo, B. Rubio, F. Molina, Y. Fujita, B. Blank, P. Ascher, J. Giovinazzo, S. Gr´evy, T. Kurtukian-Nieto, W. Gelletly, B. Bilgier, R.B. Cakirli, E. Ganioglu, H.C. Kozer, L. Kucuk, G. Susoy, L. C´aceres, O. Kamalou, C. Stodel, J.C. Thomas, H. Fujita, T. Suzuki, A. Tamii, L. Popescu, and A.M. Rogers
  • Journal Title: Acta Physica Polonica B Volume: 45 Pages: 355-362
  • DOI: 10.5506/APhysPolB.45.355
  • Peer Reviewed / Acknowledgement Compliant
• [Presentation] Identification of Cluster-like Structure by the Comparison of Gamow-Teller and E0 Transitions (2015)
  • Author(s): Y. Fujita
  • Organizer: International Molecule-type Workshop "Structure and reaction of light Exotic Nuclei"
  • Place of Presentation: Yukawa Institute, Kyoto Univ., Kyoto, Japan
  • Year and Date: 2015-01-06 – 2015-01-23
• [Presentation] Nuclear Structure Reflected in Gamow-Teller Transitions (2014)
  • Author(s): Y. Fujita
  • Organizer: Progress in Nuclear Shell Model Calculations in CNS-RIKEN collaboration
  • Place of Presentation: RIKEN Nishina Hall, Wako, Saitama, Japan
  • Year and Date: 2014-11-26 – 2014-11-28
  • Invited
• [Presentation] Charge Exchange Reaction at an Intermediate Incoming Energy (2014)
  • Author(s): Y. Fujita
  • Organizer: 4th Joint Meeting of Nuclear Physics Division APS & JPS
  • Place of Presentation: Hilton Waikoloa Village, Hawaii Island, USA
  • Year and Date: 2014-10-07 – 2014-10-11
  • Invited
• [Presentation] Observation of Low- and HIgh-Energy Gamow-Teller Phonon Excitations in Nuclei (2014)
  • Author(s): Y. Fujita
  • Organizer: Erice International School of Nuclear Physics
  • Place of Presentation: E. Majorana Foundation and Center for Scientific Culture, Erice, Italy
  • Year and Date: 2014-09-16 – 2014-09-24
• [Presentation] Gamow-Teller Excitations Studied by the Weak and Strong Interactions (2014)
  • Author(s): Y. Fujita
  • Organizer: Zakopane Conference on Nuclear Physics
  • Place of Presentation: Hotel Antalowka, Zakopane, Poland
  • Year and Date: 2014-08-31 – 2014-09-07
  • Invited
• [Remarks] Welcome to Yoshi Fujita's Home Page !
  • URL: http://www.rcnp.osaka-u.ac.jp/~fujita/
• [Remarks] 大阪大学核物理研究センター 原子核実験グループ
  • URL: http://www.rcnp.osaka-u.ac.jp/Divisions/np1-a/index.html