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Study of nuclear deformation along the neutron drip line via proton inelastic scattering

Research Project

Project/Area Number 15540257
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Particle/Nuclear/Cosmic ray/Astro physics
Research InstitutionTokyo Institute of Technology

Principal Investigator

NAKAMURA Takashi  Tokyo Institute of Technology, Graduate School of Science and Engineering, Associate Professor, 大学院・理工学研究科, 助教授 (50272456)

Project Period (FY) 2003 – 2004
Project Status Completed (Fiscal Year 2004)
Budget Amount *help
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2004: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2003: ¥3,000,000 (Direct Cost: ¥3,000,000)
KeywordsRadioactive Beam / Inelastic scattering / Drip-line nuclei / Nuclear Deformation / 中性子ハロー / 魔法数の破れ / 中性子ハロー核 / 殻構造の変化
Research Abstract

We have studied inelastic scatterings of drip-line nuclei, ^<11>Be, ^<14>Be, ^<15>B, ^<17>B, ^<18>C and ^<19>C on a proton target as well as on a carbon target. In this study we aimed at exciting primarily the first excited state, which has information of deformation of these nuclei. The deformation of such nuclei have attracted much attention since the extreme neutron to proton ratio may cause the change of nuclear shell structures represented by the magicity loss, or even the decoupling effect on the valence neutrons.
In this study, not only the bound excited states which can be measured by in-beam gamma spectroscopy, but also the unbound states which can be reached by the invariant mass spectroscopy. For the latter, we have developed a new drift chamber which can measure angles of an ejectile with very high accuracy (less than 0.1 deg). We have also developed a new scheme of analyzing two-neutron events, which was essential to specify the excited state in two-neutron halo nucleus ^<1 … More 4>Be.
A series of experiments were performed at RIKEN accelerator Research facility, where the intense radioactive beam is available. The drip-line nuclei were produced by the projectile, fragmentation and purified through the fragment separator RIPS. The excitation energy was obtained either by the method mentioned above.
We have observed for the first time the 1^<st> excited state of ^<17>B in the bound excited state and that of ^<14>Be just above the particle decay threshold at Ex=1.56 MeV. The cross sections for producing the first excited states in ^<17>B and ^<15>B suggest that the effective charges for these nuclei are extremely small compared to the conventional value. This may be related to the decoupling effect which was found for the neighboring nucleus ^<16>C. As for ^<14>Be, the first excited states located at 1.56 MeV, lower than that of ^<12>Be at 2.1 MeV. This suggests that the ^<14>Be has even more melted shell structure than the case of 12Be, which was recently found as a magicity-lost nucleus. However, the deformation parameter extracted for ^<14>Be was smaller than that of 12Be. This may be understood as a restoration of shell stability. This interesting findings are to be further studied with theories including the shell melting or cluster nature of these nuclei. For other nuclei, we have also observed a new state as well.
We are now planning to use the different probe of alpha target, an ideal isoscalar probe. This may clarify the shape difference between the neutron distribution and the proton distribution. For the very extreme neutron/proton ratios, we expect more decoupled situation where neutrons moves independently of protons. Studies of such very exotic excitation is important to understand the behavior of very neutron rich nuclei. Less

Report

(3 results)
  • 2004 Annual Research Report   Final Research Report Summary
  • 2003 Annual Research Report
  • Research Products

    (43 results)

All 2006 2005 2004 2003 Other

All Journal Article (38 results) Publications (5 results)

  • [Journal Article] Observation of strong low-lying El strength in the two-neutron halo nucleus ^<11>Li2006

    • Author(s)
      T.Nakamura et al.
    • Journal Title

      Phys. Rev. Lett. (印刷中)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Observation of strong low-lying E1 strength in the two-neutron halo nucleus ^<11>Li2006

    • Author(s)
      T.Nakamura, A.M.Vinodkumar, T.Sugimoto, et al.
    • Journal Title

      Phys.Rev.Lett. (in press)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] In-beam gamma-ray spectroscopy of neutron-rich boron isotopes ^<15,17>B via inelastic scattering on 12C2005

    • Author(s)
      Y.kondo et al.
    • Journal Title

      Phys. Rev. C 71

      Pages: 44611-44611

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Sensitivity of r-process Nucleosynthesis to Light Element Nuclear Reactions2005

    • Author(s)
      T.Sasaqui et al.
    • Journal Title

      Astrophys. J. 634

      Pages: 1173-1173

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] In-beam γ-ray spectroscopy of neutron-rich boron isotopes ^<15,17>B via inelastic scattering on ^<12>C2005

    • Author(s)
      Y.Kondo, T.Nakamura, et al.
    • Journal Title

      Phys.Rev.C 71

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Sensitivity of r-process Nucleosynthesis to Light Element Nuclear Reactions2005

    • Author(s)
      T.Sasaqui, T.Kajino, G.J.Mathews, K.Otsuki, T.Nakamura
    • Journal Title

      Astrophys.J 634

      Pages: 1173-1189

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] In-beam γ-ray spectroscopy of the neutron-rich boron isotopes ^<15,17>B via inelastic scattering on ^<12>C2005

    • Author(s)
      Y.Kondo, T.Nakamura et al.
    • Journal Title

      Physical Review C (In press)

    • Related Report
      2004 Annual Research Report
  • [Journal Article] Coulomb and nuclear breakup of a halo nucleus 11Be2004

    • Author(s)
      N.Fukuda et al.
    • Journal Title

      Phys. Rev. C 70

      Pages: 54606-54606

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Coulomb and nuclear breakup of halo nuclei2004

    • Author(s)
      T.Nakamura et al.
    • Journal Title

      Nuc1. Phys. A 738

      Pages: 283-283

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Anomalously Hindered E2 Strength B(E2;2^+_1to O^+)2004

    • Author(s)
      N.Imai et al.
    • Journal Title

      Phys. Rev. Lett. 92

      Pages: 62501-62501

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Discovery of a strange tribaryon SO(3115)in ^4He(stopped k-_3P)reaction2004

    • Author(s)
      T.Suzuki et al.
    • Journal Title

      Phys. Lett. B 597

      Pages: 263-263

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Coulomb and nuclear breakup of halo nuclei2004

    • Author(s)
      T.Nakamura
    • Journal Title

      Nuc1. Phys. A 734

      Pages: 319-319

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] ^<11>Be continuum studied through proton scattering2004

    • Author(s)
      A.Shrivastava et al.
    • Journal Title

      Phys. Lett. B 596

      Pages: 54-54

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Molecular states in neutron-rich beryllium isotopes2004

    • Author(s)
      A.Saito et al.
    • Journal Title

      Nuc1. Phys. A 738

      Pages: 337-337

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Study of the Stellar ^<22>Mg(P,gamma)^23Al Reaction using the coulomb dissociation method2004

    • Author(s)
      T.Gomi et al.
    • Journal Title

      Nuc1. Phys. A 734

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] The first excited state of ^<30>Ne studied by proton inelastic scattering in reversed Kinematics2004

    • Author(s)
      Y.Yanagisawa et al.
    • Journal Title

      Phys. Lett. B 566

      Pages: 84-84

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Coulomb and nuclear breakup of a halo nucleus ^<11>Be2004

    • Author(s)
      N.Fukuda, T.Nakamura et al.
    • Journal Title

      Phys.Rev.C 70

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Coulomb and nuclear breakup of halo nuclei2004

    • Author(s)
      T.Nakamura, N.Fukuda
    • Journal Title

      Nucl.Phys.A 738

      Pages: 283-287

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Anomalously Hindered E2 Strength B(E2,2^+_1 to 0^+)2004

    • Author(s)
      N.Imai, T.Nakamura, T.Motobayashi, et al.
    • Journal Title

      Phys.Rev.Lett. 92

      Pages: 62501-62501

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Discovery of a strange tribaryon S0(3115) in ^4He(stopped k-,p) reaction2004

    • Author(s)
      T.Suzuki, H.Bhang, R.S.Hayano, M.Iwasaki, T.Nakamura, T.Yamazaki, et al.
    • Journal Title

      Phys.Lett.B 597

      Pages: 263-269

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Coulomb and nuclear breakup of halo nuclei2004

    • Author(s)
      T.Nakamura
    • Journal Title

      Nucl.Phys.A 734

      Pages: 319-322

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] ^<11>Be continuum studied through proton scattering2004

    • Author(s)
      A.Shrivastava, Y.Blumenfeld, T.Nakamura, et al.
    • Journal Title

      Phys.Lett.B 596

      Pages: 54-60

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Molecular states in neutron-rich beryllium isotopes2004

    • Author(s)
      A.Saito, T.Motobayashi, T.Nakamura et al.
    • Journal Title

      Nucl.Phys.A 738

      Pages: 337-341

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Study of the Stellar ^<22>Mg(P,gamma)^<23> Al Reaction using the Coulomb dissociation method2004

    • Author(s)
      T.Gomi, T.Motobayashi, T.Nakamura, et al.
    • Journal Title

      Nucl.Phys.A 734

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Coulomb and nuclear breakup of a halo nucleus ^<11>Be2004

    • Author(s)
      N.Fukuda, T.Nakamura et al.
    • Journal Title

      Physical Review C 70

    • Related Report
      2004 Annual Research Report
  • [Journal Article] Anomalously Hindered E2 Strength B(E2;2^+_1→0^+) in ^<16>C2004

    • Author(s)
      N.Imai, T.Nakamura et al.
    • Journal Title

      Physical Review Letters 92

    • Related Report
      2004 Annual Research Report
  • [Journal Article] Coulomb and nuclear breakup of halo nuclei2004

    • Author(s)
      T.Nakamura, N.Fukuda
    • Journal Title

      Nuclear Physics A 738

      Pages: 283-287

    • Related Report
      2004 Annual Research Report
  • [Journal Article] ^<11>Be continuum studied through proton scattering2004

    • Author(s)
      A.Shrivastava, T.Nakamura et al.
    • Journal Title

      Physics Letters B 596

      Pages: 54-60

    • Related Report
      2004 Annual Research Report
  • [Journal Article] Discovery of a strange tribaryon S0(3115) in ^4He (stopped K^-,p) reaction2004

    • Author(s)
      T.Suzuki, T.Nakamura et al.
    • Journal Title

      Physics Letters B 597

      Pages: 263-269

    • Related Report
      2004 Annual Research Report
  • [Journal Article] Isomeric O^+ state in ^<12>Be2003

    • Author(s)
      S.Shimoura et al.
    • Journal Title

      Phys. lett. B 560

      Pages: 31-31

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] beta-decay half-lives and beta-delayed neutron multiplicities of the neutron drip-line nuclei ^<19>B,^<22>C,and^<23>N2003

    • Author(s)
      K.Yoneda et al.
    • Journal Title

      Phys. Rev. C 67

      Pages: 14316-14316

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Coulomb dissociation of halo nuclei2003

    • Author(s)
      T.Nakamura et al.
    • Journal Title

      Nucl. Phys. A 722

    • NAID

      110001196287

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Low-temperature measurement of the giant dipole resonance resonance width2003

    • Author(s)
      P.Heckman et al.
    • Journal Title

      Phys. Lett. B 555

      Pages: 43-43

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Isomeric 0^+ state in ^<12>Be2003

    • Author(s)
      S.Shimoura, T.Motobayashi, T.Nakamura, M.Ishihara, et al.
    • Journal Title

      Phys.Lett.B 560

      Pages: 31-36

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] The first excited state of ^<30>Ne studied by proton inelastic scattering in reversed kinematics2003

    • Author(s)
      Y.Yanagisawa, T.Nakamura, T.Motobayashi et al.
    • Journal Title

      Phys.Lett.B 566

      Pages: 84-89

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] beta-decay half-lives and beta-delayed neutron multiplicities of the neutron drip-line nuclei ^<19>B,^<22>C, and ^<23>N2003

    • Author(s)
      K.Yoneda, T.Nakamura, S.S.Yamamoto, et al.
    • Journal Title

      Phys.Rev.C 67

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Coulomb dissociation of halo nuclei2003

    • Author(s)
      T.Nakamura, N.Fukuda, et al.
    • Journal Title

      Nucl.Phys.A 722

    • NAID

      110001196287

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Low-temperature measurement of the giant dipole resonance width2003

    • Author(s)
      P.Heckman, D.Bazin, T.Nakamura, et al.
    • Journal Title

      Phys.Lett.B 555

      Pages: 43-48

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Publications] S.Shimoura,..., T.Nakamura et al.: "Isomeric 0+ state in 12Be"Physics Letters B. 560. 31-36 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] Y.Yanagisawa,..., T.Nakamura et al.: "The first excited state of 30Ne studied by proton inelastic scattering in reverse kinematics"Physics Letters B. 566. 84-89 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] T.Nakamura et al.: "Coulomb Dissociation of Halo Nuclei"Nuclear Physics A. 722. 301c-307c (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] K.Yoneda,..., T.Nakamura et al.: "Beta-decay half lives and beta-delayed neutronmultiplicities of the neutron drip-line nuclei 19B, 22C and 23N"Phys.Rev.C. 67. 014316-014316-7 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] N.Imai,..., T.Nakamura et al.: "Anomalously Hindered E2 Strength B(E2, 2+ to 0+) in 16C"Physical Review Letters. 92. 062501-062501-4 (2004)

    • Related Report
      2003 Annual Research Report

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Published: 2003-04-01   Modified: 2016-04-21  

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