M. Takashina

Osaka University, Suita, Osaka-fu, Japan

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Publications (36)70.41 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The differential cross sections of the 16O(p,d) reaction populating the ground state and several low-lying excited states in 15O were measured using 198-, 295- and 392-MeV proton beams at the Research Center for Nuclear Physics (RCNP), Osaka University, to study the effect of the tensor interactions in 16O. Dividing the cross sections for each excited state by the one for the ground state and comparing the ratios over a wide range of momentum transfer, we found a marked enhancement of the ratio for the positive-parity state(s). The observation is consistent with large components of high-momentum neutrons in the ground-state configurations of 16O due possibly to the tensor interactions.
    Journal of Physics Conference Series 01/2014; 569(1).
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    ABSTRACT: We have measured the 16O(p, d) reaction using 198-, 295- and 392-MeV proton beams to search for a direct evidence on an effect of the tensor interactions in light nucleus. Differential cross sections of the one-neutron transfer reaction populating the ground states and several low-lying excited states in 15O were measured. Comparing the ratios of the cross sections for each excited state to the one for the ground state over a wide range of momentum transfer, we found a marked enhancement of the ratio for the positive-parity state(s). The observation is consistent with large components of high-momentum neutrons in the initial ground-state configurations due to the tensor interactions.
    Physics Letters B 10/2013; 725(4-5):277-281. · 4.57 Impact Factor
  • Physical Review C 06/2012; · 3.72 Impact Factor
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    ABSTRACT: We have measured 16O(p,d) reaction using 198-, 295- and 392-MeV proton beams to search for a direct evidence on the effect of the tensor interactions in light nucleus. Differential cross sections of the one-neutron transfer reactions populating the ground states and several low-lying excited states in 15O were measured. Comparing the ratios of the cross sections for each excited state to the one for the ground state over a wide range of momentum transfer, we found a marked enhancement for the positive-parity state(s). The observation indicates large components of high-momentum neutrons in the initial ground-state configurations, due possibly to the tensor interactions.
    The European Physical Journal Conferences 05/2012; 66.
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    ABSTRACT: We present a new global optical potential (GOP) for nucleus-nucleus systems, including neutron-rich and proton-rich isotopes, in the energy range of $50 \sim 400$ MeV/u. The GOP is derived from the microscopic folding model with the complex $G$-matrix interaction CEG07 and the global density presented by S{\~ a}o Paulo group. The folding model well accounts for realistic complex optical potentials of nucleus-nucleus systems and reproduces the existing elastic scattering data for stable heavy-ion projectiles at incident energies above 50 MeV/u. We then calculate the folding-model potentials (FMPs) for projectiles of even-even isotopes, $^{8-22}$C, $^{12-24}$O, $^{16-38}$Ne, $^{20-40}$Mg, $^{22-48}$Si, $^{26-52}$S, $^{30-62}$Ar, and $^{34-70}$Ca, scattered by stable target nuclei of $^{12}$C, $^{16}$O, $^{28}$Si, $^{40}$Ca $^{58}$Ni, $^{90}$Zr, $^{120}$Sn, and $^{208}$Pb at the incident energy of 50, 60, 70, 80, 100, 120, 140, 160, 180, 200, 250, 300, 350, and 400 MeV/u. The calculated FMP is represented, with a sufficient accuracy, by a linear combination of 10-range Gaussian functions. The expansion coefficients depend on the incident energy, the projectile and target mass numbers and the projectile atomic number, while the range parameters are taken to depend only on the projectile and target mass numbers. The adequate mass region of the present GOP by the global density is inspected in comparison with FMP by realistic density. The full set of the range parameters and the coefficients for all the projectile-target combinations at each incident energy are provided on a permanent open-access website together with a Fortran program for calculating the microscopic-basis GOP (MGOP) for a desired projectile nucleus by the spline interpolation over the incident energy and the target mass number.
    Physical Review C 04/2012; 85(4). · 3.72 Impact Factor
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    ABSTRACT: We investigate the α+d elastic scattering and the radiative capture reaction of 2H(α, γ)6Li based on the α + p + n three-body model. The α+d scattering states are described by using the complex-scaled solutions of the Lippmann-Schwinger equation. We calculate the elastic phase shifts for the α+d scattering and the radiative capture cross section of 6Li. We evaluate the contributions of the α + p + n structures in those observables. It is found that in the α+d scattering process, the deuteron breakup and the rearrangement to the 5He + p and 5Li + n channels play prominent roles in reproducing the observed phase shifts and radiative capture cross section.
    Physical Review C 12/2011; 84(6). · 3.72 Impact Factor
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    ABSTRACT: We investigate the three-body Coulomb breakup of a two-neutron halo nucleus, 6He. We calculate the breakup cross section and the invariant mass spectra by using the complex-scaled solutions of the Lippmann-Schwinger equation, and discuss the relations between the structures in these observables and the n-n and alpha-n correlations in 6He.
    International Journal of Modern Physics E 01/2011; 20:843-846. · 0.63 Impact Factor
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    ABSTRACT: The neutron-rich nucleus 74Ni was studied with inverse-kinematics inelastic proton scattering using a 74Ni radioactive beam incident on a liquid hydrogen targetat a center-of-mass energy of 80 MeV. From the measured de-excitation gamma-rays, the population of the first 2+ state was quantified. The angle-integrated excitation cross section was determined to be 14(4) mb. A deformation length of delta = 1.04(16) fm was extracted in comparison with distorted wave theory, which suggests that the enhancement of collectivity established for 70Ni continues up to 74Ni. A comparison with results of shell model and quasi-particle random phase approximation calculations indicates that the magic character of Z = 28 or N = 50 is weakened in 74Ni.
    Physics Letters B 08/2010; · 4.57 Impact Factor
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    ABSTRACT: We study theoretically the elastic scattering of B from ¹²C at E{sub lab}=95 MeV. The B nucleus consists of weakly bound Be and proton, while the Be nucleus has an internal cluster structure of alpha+³He. We treat the last proton in B in the adiabatic recoil approximation and also take into account the excitation of Be including resonance states by a coupled-channel method with consideration of the cluster structure. It turns out that the excitation to the resonance state of Be in B is important for the B elastic scattering.
    Physical Review C 06/2010; 81(6):061602-061602. · 3.72 Impact Factor
  • M. Takashina, T. Furumoto, Y. Sakuragi
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    ABSTRACT: We reanalyze the 16O+16O inelastic scattering to the single 21+ and 31- excitation channels at an incident energy of Elab=1120 MeV by a microscopic coupled-channel (CC) calculation with complex G-matrix interaction. The imaginary part of the folded potential is renormalized so as to reproduce the elastic angular distribution. It is found that the results of full CC calculations are still inconsistent with the experimental data for both 21+ and 31- channels. It is also found that when the imaginary coupling terms are omitted, the calculated 21+-channel cross sections are improved, although the 31--channel cross sections are slightly overestimated.
    Physical Review C 04/2010; 81(4). · 3.72 Impact Factor
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    ABSTRACT: We investigate the three-body Coulomb breakup of a two-neutron halo nucleus, He. Based on the alpha+n+n model, the three-body scattering states of He are described by using the combined methods of the complex scaling and the Lippmann-Schwinger equation. We calculate the breakup cross section, the two-dimensional energy distributions, and the invariant mass spectra for the E1 transition of He. We discuss the relations between the structures in these strengths and the n-n and alpha-n correlations of He. It is found that the He resonance in the final states contributes to make a low-energy enhancement of the strength. The n-n final-state interaction also contributes to enhance the strength globally. However, the ground-state correlations of He, such as a dineutron, are difficult to recognize in the strength because of the dominant effect of the final-state interaction.
    Physical Review C 04/2010; 81(4):044308-044308. · 3.72 Impact Factor
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    ABSTRACT: We investigate the three-body Coulomb breakup of a two-neutron halo nucleus, 6He. The three-body scattering states of 6He are described by using the Complex-scaled solutions of the Lippmann-Schwinger equation. We calculate the breakup cross section and the invariant mass spectra, and discuss the relations between the structures in these observables and the n-n and alpha-n correlations of 6He.
    Modern Physics Letters A 01/2010; 25:1907-1910. · 1.11 Impact Factor
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    ABSTRACT: Nuclear breakup process is very important for light unstable nuclei (typically halo nuclei) induced reactions because of their weak-binding nature. The continuum-discretized coupled-channel (CDCC) method is known to be one of the powerful method to describe the nuclear breakup reaction. Indeed, CDCC has been applied to a number of analyses for the breakup reactions of both the stable and unstable nuclei, and the successful results have been obtained. In the present study, we propose complex-scaled CDCC (CS-CDCC) method, in which only the internal coordinate and momentum of the projectile are complex-scaled. The expected advantages of CS-CDCC are (1) in spite of the discretization, we can obtain the continuous S matrix elements without the smoothing function, because the continuum level density is correctly obtained, (2) in the framework of the complex scaling method, three-body scattering state can be solved properly, (3) the resonance state is strictly separated from the continuum states, and this fact is more advantageous for investigation of reaction mechanism than the ordinary CDCC method. We apply CS-CDCC to the d ->p+n breakup reaction on a ^58Ni target at Ed=80 MeV to confirm the availability of CS-CDCC. We also plan to apply it to breakup reactions of light unstable nuclei.
    10/2009;
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    ABSTRACT: The ^11Li nucleus has characteristc features of neutron-rich nuclei such as two-neutron halo structure and large s-wave mixing in the ground state, and has been studied with keen interest from both theoretical and experimental sides. Experimentally, the Coulomb breakup reactions have been performed to investigate the exotic features of ^11Li, and significant E1 strength was measured at low excitation energy. However, the nature of this soft E1 excitation for ^11Li is not clearly understood. To understand the nature of the soft E1 excitation, it is necessary to understand the complicated structure of ^11Li, which contains both ^9Li-n and n- n correlations. In the present study, we investigate soft E1 excitation for ^11Li based on the core+n+n three-body model. We analyze the E1 strength as a function of relative energies in binary subsystems in ^11Li, and discuss the correlations of ^9Li-n and n-n subsystems through the soft E1 excitation.
    10/2009;
  • M. Takashina, Y. Sakuragi
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    ABSTRACT: We have analyzed 16O+16O inelastic scattering to the single 21+ and 31- channels at incident energies of Elab=350 and 1120 MeV by a microscopic coupled-channel calculation. We have found that the strong rotational coupling among the channels of the α+12Cg.s. type cluster states plays an important role in reproducing the angular distribution of the 21+ channel for both energies. We have also found that the coupling with the 02+, 21+, and 41+ channels as well as those among the shell channels has a large effect on the 31- channel cross sections at Elab=350 MeV. However, their absolute values could not be reproduced by our calculation, unless we assumed that the strengths of the 31-→02+,21+,41+ transitions were unphysically strong.
    Physical Review C 07/2009; 80(1). · 3.72 Impact Factor
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    ABSTRACT: Proton inelastic scattering on the neutron-rich nucleus 32Mg has been studied at 46.5 MeV/nucleon in inverse kinematics. Populated states were identified by measuring de-excitation γ rays, in which five new states were found by γ-γ coincidence analyses. By analyzing the angular differential cross sections via coupled-channel calculations, their spins and parities were constrained and the amplitudes for each transition were extracted. The spin and parity of the 2321-keV state was assigned as 41+. The ratio between the energies of the 21+ and 41+ states indicates that 32Mg is a transitional nucleus rather than an axially deformed rigid rotor. The collectivities in the nucleus 32Mg with N=20 are discussed based on the results obtained in the present experiment.
    Phys. Rev. C. 05/2009; 79(5).
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    ABSTRACT: We propose a new method to describe three-body breakups of nuclei, in which the Lippmann-Schwinger equation is solved combining with the complex scaling method. The complex-scaled solutions of the Lippmann-Schwinger equation (CSLS) enables us to treat boundary conditions of many-body open channels correctly and to describe a many-body breakup amplitude from the ground state. The Coulomb breakup cross section from the 6He ground state into 4He+n+n three-body decaying states as a function of the total excitation energy is calculated by using CSLS, and the result well reproduces the experimental data. Furthermore, the two-dimensional energy distribution of the E1 transition strength is obtained and an importance of the 5He(3/2-) resonance is confirmed. It is shown that CSLS is a promising method to investigate correlations of subsystems in three-body breakup reactions of the weakly-bound nuclei. Comment: 12 pages, 6 figures, submitted to Progress of Theoretical Physics; section 2.4 added, 2 equations added, 1 equation replaced
    Progress of Theoretical Physics 05/2009; · 2.48 Impact Factor
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    ABSTRACT: The very neutron-rich nucleus 20C has been investigated by inelastic scattering on 208Pb and liquid hydrogen targets. Through distorted wave analysis, the reduced electric quadrupole transition probability B(E2;0g.s.+→21+)<18.4 (stat) e2 fm4 and the neutron transition probability Mn2=292±52 (stat) fm4 have been derived. A simple shell model calculation has shown a need for a factor of about 0.4 decrease of the normal polarization charges to elucidate the results. This is interpreted as a decoupling of the valence neutrons from the nuclear core in carbon isotopes heavier than 14C.
    Physical Review C 01/2009; 79(1). · 3.72 Impact Factor
  • M. Takashina
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    ABSTRACT: We analyze α inelastic scattering on 12C exciting the 02+ state at the incident energy of Eα=240 MeV using the eikonal wave Born approximation and investigate what determines the oscillation pattern appearing in the inelastic angular distribution. We present an interpretation for the results obtained by the present author and his collaborator [Phys. Rev. C 74, 054606 (2006)] that the oscillation pattern in inelastic angular distribution is almost independent of the nuclear radius of 12C(02+).
    Phys. Rev. C. 07/2008; 78(1).
  • M Takashina, Y Kanada-En'yo
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    ABSTRACT: Proton inelastic scattering on 12Be was studied by microscopic coupled-channel calculations with theoretical wave function of 12Be obtained by the antisymmetrized molecular dynamics. The experimental angular distribution of the inelastic scattering exciting to the 21+ state in Be was successfully reproduced by the largely deformed states with dominant sd-shell configuration in the ground band. It was also shown that the difference of the radial dependence between the proton transition density and neutron one should be considered carefully in the inelastic scattering study of unstable nuclei.
    Journal of Physics Conference Series 05/2008; 111(1):012018.

Publication Stats

80 Citations
70.41 Total Impact Points

Institutions

  • 2009–2012
    • Osaka University
      • • Graduate School of Medicine
      • • Research Center for Nuclear Physics
      Suita, Osaka-fu, Japan
  • 2006–2008
    • Kyoto University
      • Yukawa Institute for Theoretical Physics
      Kyoto, Kyoto-fu, Japan
  • 2005
    • RIKEN
      Вако, Saitama, Japan
  • 2003
    • Osaka City University
      • Department of Physics
      Ōsaka, Ōsaka, Japan