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• Information Initiative Center　Digital Contents

Affiliation (Master)

• Information Initiative Center　Digital Contents

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• Name (Japanese)

  Hirabayashi

• Name (Kana)

  Yoshiharu

• Name

  200901025225190306

Achievement

Research Areas

• Natural sciences / Theoretical studies related to particle-, nuclear-, cosmic ray and astro-physics

Published Papers

• Production spectra with a Σ- hyperon in (π-, K+) reactions on light to heavy nuclei

  Toru Harada, Yoshiharu Hirabayashi

  Physical Review C 107 (5) 054611-1 - 054611-20 2469-9985 2023/05/19 [Refereed]
  
• alpha+92Zr cluster structure in 96Mo

  S. Ohkubo, Y. Hirabayashi

  Physical Review C 107 (3) 034317/1 - 034317/7 2023/03/29 [Refereed]
  
• Extended optimal Fermi averaging for near-recoilless Λ production in the (K-, π-) reaction on nuclei

  Toru Harada, Yoshiharu Hirabayashi

  Physical Review C 105 (6) 064606-1 - 064606-7 2469-9985 2022/06/15 [Refereed]
   

  We propose to extend the optimal Fermi averaging procedure theoretically in order to calculate an in-medium K???n n???n amplitude for the exothermic (K???, n???) reaction on nuclei in the framework of a distorted-wave impulse approximation, taking into account the local momentum transfer generated by semiclassical distorted waves for K??? and n??? mesons. Angular distributions for the 12C(K???, n???) n12 C reaction in which a momentum transfer is q < 80 MeV/c at pK = 800 MeV/c in the n??? forward direction are estimated by applying the extended procedure. The result shows that the calculated angular distributions are in good agreement with those of the data, and this extension is a successful prescription making it possible to describe the reaction cross sections in near-recoilless reactions such as (K???, n???) in our framework.
• Production cross sections of Λ3,4H bound states in 3,4He(K−, π0) reactions at 1 GeV/c

  Toru Harada, Yoshiharu Hirabayashi

  Nuclear Physics A 1015 122301 - 122301 0375-9474 2021/11 [Refereed]
   

  We investigate theoretically productions of H-3,4(Lambda) bound states in the exothermic (K-, pi(0)) reactions on He-3,He-4 targets at p(K)- = 1.0 GeV/c in a distorted-wave impulse approximation with the optimal Fermi averaging K- p -> pi(0)Lambda t matrix. We calculate angular distributions of the laboratory differential cross sections do-MS-flab and the integrated cross sections sigma(lab) for a J(P) = 0(+) ground state and a J(P) = 1(+) excited state of H-4(Lambda) at pi(0) forward-direction angles of theta(lab) = 0 degrees-20 degrees, and those for a J(P) = 1/2+ ground state of H-3(Lambda). The production of a J(P) = 3/2(+) excited state of H-3(Lambda) as a virtual state is also evaluated. The comparison in d sigma/d Omega(lab) and sigma(lab) between H-4(Lambda) and H-3(Lambda) provides examining the mechanism of the 3 4 production and structure of (3,4)(Lambda), as well as in the endothermic (pi(-), K-0) reactions at p(pi)- = 1.05 GeV/c. This investigation confirms the feasibility of lifetime measurements of H-3(Lambda) at the J-PARC experiments. (C) 2021 Elsevier B.V. All rights reserved.
• Existence of core excited 8Be* = α+α* cluster structure in α+α scattering

  Yoshiharu Hirabayashi, Shigeo Ohkubo

  Progress of Theoretical and Experimental Physics 2021 (10) 2021/10/04 [Refereed]
   

  We show the existence of the α+α * cluster structure at the highly excited energy around Ex =20 MeV in 8Be for the first time in the coupled channels calculations. An extended double folding model derived using a realistic precise cluster wave function with a well-developed N+3N cluster structure for the first excited state of 4He was employed. The calculation reproduces the experimental phase shifts in α+α scattering up to Ec.m. =21 MeV well. The result shows that the well-developed core-excited α+α * structure appears as resonances for L=0 and 2 near the α+α * threshold which correspond to the experimental states at Ex =20.20MeV and Ex =22.24MeV in 8Be.
• Ξ-nucleus potential for Ξ− quasifree production in the Be9(K−,K+) reaction

  Toru Harada, Yoshiharu Hirabayashi

  Physical Review C 103 (2) 024605-1 - 024605-8 2469-9985 2021/02/03 [Refereed]
   

  We study phenomenologically a Xi(-) production spectrum of the Be-9(K-, K+) reaction at 1.8 GeV/c within the distorted-wave impulse approximation using the optimal Fermi-averaged K- p -> K+ Xi(-) amplitude. We attempt to clarify properties of a Xi -nucleus potential for Xi(-)-Li-8, comparing the calculated spectrum with the data of the BNL-E906 experiment. The results show a weak attraction in the Xi-nucleus potential for Xi(-)-Li-8, which can sufficiently explain the data in the Xi(-) quasifree region. The strength of V-0(Xi) = 17 +/- 6 MeV is favored within the Woods-Saxon potential, accompanied by the reasonable absorption of W-0(Xi) = 5 MeV for Xi(-) p -> Xi(0)n and Xi(-) p -> Lambda Lambda transitions in nuclear medium. It is difficult to determine the value of W-0(Xi) from the data due to the insufficient resolution of 14.7 MeV FWHM. The energy dependence of the Fermi-averaged K- -> p -> K+ amplitude is is also confirmed by this analysis, and its importance in the nuclear (K-, K+) reaction is emphasized.
• Medium effects on Ξ− production in the nuclear (K−,K+) reaction

  Toru Harada, Yoshiharu Hirabayashi

  Physical Review C 102 (2) 024618-1 - 024618-8 2469-9985 2020/08/17 [Refereed]
   

  We study theoretically medium effects on Xi(-) production in the (K-, K+) reaction, using the optimal Fermi -averaging procedure, which describes the Fermi motion of a nucleon on the on-energy-shell K- p -> K+Xi(-) reaction condition in nuclei. The results show the strong energy and angular dependencies of the in-medium K(-)p -> K+Xi(-) cross section, which affect significantly the shape and the magnitude of the production spectrum for Xi(-)-hypernuclear states in the (K-, K+) reaction on a nuclear target. The application to the Xi(-) quasifree production via the (K-, K+) reaction on a C-12 target is also discussed in a Fermi gas model.
• Analysis of the 16O(p, pn)15O Reaction Using the CDCC Method

  Dagvadorj Ichinkhorloo, Masayuki Aikawa, Satoshi Chiba, Yoshiharu Hirabayashi, Kiyoshi Katō

  Proceedings of 13th International Conference on Nucleus-Nucleus Collisions 32 0101000-1 - 0101000-3 2020/07/16 [Refereed][Not invited]
  
• Production Spectra of ³He(π,K) Reactions with Continuum Discretized Coupled Channels

  Harada Toru, Hirabayashi Yoshiharu

  Meeting Abstracts of the Physical Society of Japan 一般社団法人 日本物理学会 75.1 232 - 232 2020
• 1. Production of a 4He hypernucleus in the 4He(π,K) reactions reexamined

  HIRABAYASHI Yoshiharu

  Physical Revidew C 100 (2) 024605-1 - 024605-11 2019/08 [Refereed][Not invited]
  
• Production spectra of hypernuclear excited states by (pi,K) reactions

  Harada Toru, Hirabayashi Yoshiharu

  Meeting Abstracts of the Physical Society of Japan 一般社団法人 日本物理学会 74.1 347 - 347 2019
• Repulsion and absorption of the Σ -nucleus potential for Σ - He 5 in the Li 6 (π-,K+) reaction

  Toru Harada, Ryotaro Honda, Yoshiharu Hirabayashi

  Physical Review C 97 (2) 024601-1 - 024601-13 2469-9993 2018/02/01 [Refereed][Not invited]
   

  We study phenomenologically inclusive spectra of the Li6(π-,K+) reaction at 1.2 GeV/c within a distorted-wave impulse approximation with the optimal Fermi-averaging π-p→K+Σ-t matrix. We attempt to clarify the property of a Σ-nucleus potential for Σ - He5 by comparing the calculated spectra with the data of the J-PARC E10 experiment. The result shows that the repulsive and absorptive components of the Σ - He5 potential provide the ability to explain the data of the continuum spectra in Σ and Λ regions the strengths of VΣ=+30±10 MeV and WΣ=-26±2 MeV are favored within the Woods-Saxon potential, consistent with analyses for heavier nuclei. Effects of the size and potential range for Σ - He5 in the neutron excess of (N-Z)/(N+Z)= 0.2 are also discussed.
• Production of hypernuclear excited states by (pi,K+) reactions

  Harada Toru, Hirabayashi Yoshiharu

  Meeting Abstracts of the Physical Society of Japan 一般社団法人 日本物理学会 73.1 266 - 266 2018
• Existence of inelastic supernumerary nuclear rainbow in O-16+C-12 scattering

  S. Ohkubo, Y. Hirabayashi, A. A. Ogloblin

  PHYSICAL REVIEW C 96 (2) 024607-1 - 024607-6 2469-9985 2017/08 [Refereed][Not invited]
   

  The existence of a supernumerary nuclear rainbow in inelastic scattering is reported. This is done by studying inelastic O-16 scattering from C-12, exciting the 2(+) (4.44 MeV) state of C-12 and elastic scattering at the incident energies in the range 124-200 MeV, using the coupled channels method. An extended double folding potential is used. This is derived from realistic wave functions for C-12 and O-16 calculated with a microscopic a cluster model and a finite-range density-dependent nucleon-nucleon force. Excitations to the 2(+) (4.44 MeV), 3(-)(9.64 MeV), and 4(+) (14.08 MeV) states of C-12, and the 3(-)(6.13 MeV) and 2(+) (6.92 MeV) states of O-16 are included in the coupled channels calculations. The emergence of the supernumerary bow is understood by the properties of both the Luneburg-lens-like potential in the internal region and diffuse attraction in the outer region. The existence of a supernumerary rainbow for inelastic scattering in addition to the existence of a dynamically created secondary rainbow and a dynamically refracted primary rainbow for elastic scattering, which are not observed in meteorological rainbows, further deepens the understanding of nuclear rainbows.
• Low energy scattering cross sections for n + 6Li and n + 7Li reactions

  D. Ichinkhorloo, M. Aikawa, S. Chiba, Y.Hirabayashi, K. Kato

  Proceedings of the 7th AASPP Workshop on Asian Nuclear Reaction Database Development 51 - 68 2017/06 [Not refereed][Not invited]
  
• Production of a neutron-rich H-6(Lambda) hypernucleus in the Li-6(pi(-), K+) reaction

  Toru Harada, Yoshiharu Hirabayashi

  PHYSICAL REVIEW C 95 (4) 044610-1 - 044610-10 2469-9985 2017/04 [Refereed][Not invited]
   

  We study phenomenologically the production of the neutron-rich hypernucleus H-6(Lambda) in the Li-6(pi(-), K+) reaction at 1.2 GeV/c, using a distorted-wave impulse approximation in a one-step mechanism, pi(-) p -> K+ Sigma(-) via Sigma(-) doorways caused by Sigma(-) p <-> Lambda n coupling. The production cross section of H-6(Lambda)(1(exc.)(+)) is evaluated by a coupled (H-5- Lambda) + (He-5-Sigma(-)) model with a spreading potential, in comparison with the data of the missing mass spectrum at the J-PARC E10 experiment. The result indicates that the Sigma(-) mixing probabilities in H-6(Lambda)(1(exc.)(+)) are P Sigma- < similar to 0.2% both for s(Sigma) state and for p(Sigma) state in order to reproduce no significant peak in the Lambda production data, so that the cross section of H-6(Lambda) is less than on the order of 0.4 nb/sr. The sensitivity of the Sigma Lambda coupling and Lambda potentials to the near-Lambda-threshold spectrum is discussed. The shape and magnitude of the spectrum provide valuable information on the Sigma Lambda coupling in the production mechanism and also the nuclear structure of H-6(Lambda)(1(exc.)(+)).
• ⁶Li(π^-, K⁺) reaction and properties of the Σ-nucleus potential

  Harada Toru, Hirabayashi Yoshiharu

  Meeting Abstracts of the Physical Society of Japan 一般社団法人 日本物理学会 72.2 273 - 273 2017
• The Continuum Discretized Coupled Channels Method to Nucleon-Induced Reactions on 6,7Li

  D. Ichinkhorloo, M. Aikawa, S. Chiba, Y. Hirabayashi, K. Kato

  Mongolian Journal of Physics 2 209 - 217 2016/12 [Not refereed][Not invited]
  
• Evidence for a dynamically refracted primary bow in weakly bound Be-9 rainbow scattering from O-16

  S. Ohkubo, Y. Hirabayashi

  PHYSICAL REVIEW C 94 (3) 034601-1 - 034601-5 2469-9985 2016/09 [Refereed][Not invited]
   

  We present for the first time evidence for the existence of a dynamically refracted primary bow for Be-9 + O-16 scattering. This is demonstrated through the use of coupled channel calculations with an extended double folding potential derived from the density-dependent effective two-body force and precise microscopic cluster wave functions for Be-9. The calculations reproduce the experimental Airy structure in Be-9 + O-16 scattering well. It is found that coupling of a weakly bound 9Be nucleus to excited states plays the role of a booster lens, dynamically enhancing the refraction over the static refraction due to the Luneburg lens mean field potential between the ground states of Be-9 and O-16.
• Low energy scattering cross sections for n + Li-6,Li-7 reactions using the continuum-discretized coupled-channels method

  D. Ichinkhorloo, M. Aikawa, S. Chiba, Y. Hirabayashi, K. Kato

  PHYSICAL REVIEW C 93 (6) 064612-1 - 064612-7 2469-9985 2016/06 [Refereed][Not invited]
   

  We study the integrated elastic and inelastic scattering cross sections together with their angular distributions of n + Li-6,Li-7 using n+ (alpha + d) and n+ (alpha + t) cluster models, respectively, and the continuum-discretized coupled-channel framework. The microscopic single-folding potential is used for the neutron energies from 1 to 24 MeV. The calculated elastic and inelastic scattering cross sections are in good agreement with experimental and evaluated data for the observed incident energies.
• Calculation of the scattering cross section for 6Li+n reactions

  D. Ichinkhorloo, M. Aikawa, S. Chiba, Y.Hirabayashi, K. Kato

  Proceedings of the 2014 Symposium on Nuclear Data 285 - 290 2016/03 [Refereed][Not invited]
  
• 21pAC-7 Poles of the S matrix for the P-wave ^4_ΣHe hypernucleus on Riemann sheets

  Harada T., Hirabayashi Y.

  Meeting Abstracts of the Physical Society of Japan 一般社団法人日本物理学会 71 386 - 386 2189-079X 2016
• The scattering cross sections for Li-6,Li-7 + n reactions

  D. Ichinkhorloo, M. Aikawa, S. Chiba, Y. Hirabayashi, K. Kato

  CNR*15 - 5TH INTERNATIONAL WORKSHOP ON COMPOUND-NUCLEAR REACTIONS AND RELATED TOPICS 122 2100-014X 2016 [Refereed][Not invited]
   

  We investigate the continuum-discretized coupled-channel analysis to the integrated elastic and inelastic scattering cross sections for Li-6,Li-7 + n reactions. We used the JeukenneLejeune-Mahaux effective nucleon-nucleon interaction and optical model potential at incident neutron energies below and above 10 MeV, respectively. The calculated elastic and inelastic scattering cross sections with observed incident energies are almost in good agreement with experimental and evaluated data.
• Further evidence for a dynamically generated secondary bow in C-13+C-12 rainbow scattering

  S. Ohkubo, Y. Hirabayashi, A. A. Ogloblin

  PHYSICAL REVIEW C 92 (5) 051601-1 - 051601-5 0556-2813 2015/11 [Refereed][Not invited]
   

  The existence of a secondary bow is confirmed for C-13 + C-12 nuclear rainbow scattering in addition to the O-16 + C-12 system. This is found by studying the experimental angular distribution of C-13 + C-12 scattering at the incident C-13 energy E-L = 250 MeV with an extended double-folding (EDF) model that describes all the diagonal and off-diagonal coupling potentials derived from the microscopic wave functions for C-12 using a density-dependent nucleon-nucleon force. The Airy minimum at theta approximate to 70 degrees, which is not reproduced by a conventional folding potential, is revealed to be a secondary bow generated dynamically by a coupling to the excited state 2(+) (4.44 MeV) of C-12. The essential importance of the quadruple Y2 term (reorientation term) of potential of the excited state 2(+) of C-12 for the emergence of a secondary bow is found. The mechanism of the secondary bow is intuitively explained by showing how the trajectories are refracted dynamically into the classically forbidden angular region beyond the rainbow angle of the primary rainbow.
• Airy structure in O 16 + C 14 nuclear rainbow scattering

  S. Ohkubo, Y. Hirabayashi

  Physical Review C - Nuclear Physics 92 (2) 1089-490X 2015/08/31 [Refereed][Not invited]
   

  The Airy structure in 16O+14C rainbow scattering is studied with an extended double-folding (EDF) model that describes all the diagonal and off-diagonal coupling potentials derived from the microscopic realistic wave functions for 16O by using a density-dependent nucleon-nucleon force. The experimental angular distributions at EL=132, 281, and 382.2 MeV are well reproduced by the calculations. By studying the energy evolution of the Airy structure, the Airy minimum around θ=76 in the angular distribution at EL=132 MeV is assigned as the second-order Airy minimum A2 in contrast to the recent literature which assigns it as the third order A3. The Airy minima in the 90 excitation function is investigated in comparison with well-known 16O+16O and 12C+12C systems. Evolution of the Airy structure into the molecular resonances with the 16O+14C cluster structure in the low-energy region around Ec.m.=30 MeV is discussed. It is predicted theoretically for the first time for a non-4NO16+14C system that Airy elephants in the 90 excitation function are present.
• Airy structure in O-16+C-14 nuclear rainbow scattering

  S. Ohkubo, Y. Hirabayashi

  PHYSICAL REVIEW C 92 (2) 024624-1 - 024624-5 2469-9985 2015/08 [Refereed][Not invited]
   

  The Airy structure in O-16 + C-14 rainbow scattering is studied with an extended double-folding (EDF) model that describes all the diagonal and off-diagonal coupling potentials derived from the microscopic realistic wave functions for O-16 by using a density-dependent nucleon-nucleon force. The experimental angular distributions at E-L = 132, 281, and 382.2 MeV are well reproduced by the calculations. By studying the energy evolution of the Airy structure, the Airy minimum around theta = 76 degrees in the angular distribution at E-L = 132 MeV is assigned as the second-order Airy minimum A2 in contrast to the recent literature which assigns it as the third order A3. The Airy minima in the 90 degrees excitation function is investigated in comparison with well-known O-16 + O-16 and C-12 + C-12 systems. Evolution of the Airy structure into the molecular resonances with the O-16 + C-14 cluster structure in the low-energy region around E-c.m. = 30 MeV is discussed. It is predicted theoretically for the first time for a non-4N O-16 + C-14 system that Airy elephants in the 90 degrees excitation function are present.
• Emergence of a secondary rainbow and the dynamical polarization potential for O-16 on C-12 at 330 MeV

  R. S. Mackintosh, Y. Hirabayashi, S. Ohkubo

  PHYSICAL REVIEW C 91 (2) 024616-1 - 024616-8 0556-2813 2015/02 [Refereed][Not invited]
   

  Background: It was shown recently that an anomaly in the elastic scattering of O-16 on C-12 at around 300 MeV is resolved by including within the scattering model the inelastic excitation of specific collective excitations of both nuclei, leading to a secondary rainbow. There is very little systematic knowledge concerning the contribution of collective excitations to the interaction between nuclei, particularly in the overlap region when neither interacting nuclei are light nuclei. Purpose: Our goals are to study the dynamic polarization potential (DPP) generated by channel coupling that has been experimentally validated for a case (O-16 on C-12 at around 300 MeV) where scattering is sensitive to the nuclear potential over a wide radial range; to exhibit evidence of the nonlocality due to collective coupling; to validate, or otherwise invalidate, the representation of the DPP by uniform renormalizing folding models or global potentials. Methods: S-matrix to potential, S-L -> V (r), inversion yields local potentials that reproduce the elastic channel S matrix of coupled channel calculations. Subtracting the elastic channel uncoupled potential yields a local L-independent representation of the DPP. The dependence of the DPP on the nature of the coupled states and other parameters can be studied. Results: Local DPPs were found due to the excitation of C-12 and the combined excitation of O-16 and C-12. The radial forms were different for the two cases, but each were very different from a uniform renormalization of the potential. The full coupling led to a 10% increase in the volume integral of the real potential. Evidence for the nonlocality of the underlying formal DPP and for the effect of direct coupling between the collective states is presented. Conclusions: The local DPP generating the secondary rainbow has been identified. In general, DPPs have forms that depend on the nature of the specific excitations generating them, but, as in this case, they cannot be represented by a uniform renormalization of a global model or folding model potential. The method employed herein is a useful tool for further exploration of the contribution of collective excitations to internuclear potentials, concerning which there is still remarkably little general information.
• Continuum pp Lambda spectrum of the He-3(K-, pi(-)) reaction with continuum discretized coupled channels

  Tom Harada, Yoshiharu Hirabayashi

  NUCLEAR PHYSICS A 934 8 - 17 0375-9474 2015/02 [Refereed][Not invited]
   

  We theoretically investigate an inclusive pi(-) spectrum of a He-3(K- pi(-)) reaction at 870 MeV/c in a distorted-wave impulse approximation using the continuum discretized coupled channels (CDCC) method, in order to well describe the pp Lambda continuum states above the p + p + Lambda breakup threshold. We calculate the continuum ppA states applying the multichannel Green's function with a microscopic 2N - Lambda folding-model potential constructed by the CDCC wavefunctions. The results show that the calculated spectra reproduce available experimental data, and that the pp continuum states lying in higher energies are needed to fully describe these spectra, depending on the momentum transfer in the (K- pi(-)) reaction. It is shown that this calculation provides the ability of describing three-body ppA breakup systems for the (K- pi(-)) spectra. (C) 2014 Elsevier B.V. All rights reserved.
• 27aSF-12 ^6Li(π^-,K^+) reactions and hypernuclear production spectra

  Harada T., Hirabayashi Y.

  Meeting Abstracts of the Physical Society of Japan 一般社団法人日本物理学会 70 309 - 309 2189-079X 2015
• 27aSP-4 Existence of a secondary bow in nuclear rainbow scattering and dynamical nucleus-nucleus interaction

  Ohkubo S., Hirabayashi Y., Mackintosh R.

  Meeting Abstracts of the Physical Society of Japan 一般社団法人日本物理学会 70 160 - 160 2189-079X 2015
• 24aCD-4 Production of Neutron-rich Hypernuclei via (π^-,K^+) Reactions

  Harada T., Hirabayashi Y.

  Meeting Abstracts of the Physical Society of Japan 一般社団法人日本物理学会 70 367 - 367 2189-079X 2015
• P-wave resonant state of the He-4(Sigma) hypernucleus in the He-4(K-, pi(-)) reaction

  Toru Harada, Yoshiharu Hirabayashi

  PHYSICS LETTERS B 740 312 - 316 0370-2693 2015/01 [Refereed][Not invited]
   

  We theoretically investigate a possible existence of a p-wave He-4(Sigma) resonant state with J(pi) =1(-), T similar or equal to 1/2 above the Sigma threshold, using a coupled (3N - A) + (3N-Sigma) model with a spreading potential. We calculate inclusive and Sigma-A conversion pi(-) spectra in a He-4(K-, pi(-)) reaction at 1.5 GeV/c, theta(lab) = 4-12 degrees by the Green's function method in a distorted-wave impulse approximation. The pole position for the p-wave Sigma resonant state in He-4(Sigma) is determined on the Riemann sheets in the complex E plane. The result shows that a peak of the He-4(Sigma) resonant state is clearly obtained in the conversion spectra above the X threshold, and that the angular distributions of these spectra enable extraction of the contribution of the resonant state from the pi(-) spectra. Effects of the Sigma-nucleus potential and the interference between A and X on the spectra are also discussed. (C) 2014 The Authors. Published by Elsevier B.V.
• Refractive effects and Airy structure in inelastic O 16 + C 12 rainbow scattering

  S. Ohkubo, Y. Hirabayashi, A. A. Ogloblin, Yu A. Gloukhov, A. S. Dem'Yanova, W. H. Trzaska

  Physical Review C - Nuclear Physics 90 (6) 1089-490X 2014/12/22 [Refereed][Not invited]
   

  Inelastic O16+C12 rainbow scattering to the 2+ (4.44 MeV) state of C12 was measured at the incident energies, EL = 170, 181, 200, 260, and 281 MeV. A systematic analysis of the experimental angular distributions was performed using the coupled-channels method with an extended double folding potential derived from realistic wave functions for C12 and O16 calculated with a microscopic α cluster model and a finite-range density-dependent nucleon-nucleon force. The coupled-channels analysis of the measured inelastic-scattering data shows consistently some Airy-like structure in the inelastic-scattering cross sections for the first 2+ state of C12, which is somewhat obscured and still not clearly visible in the measured data. The Airy minimum was identified from the analysis and the systematic energy evolution of the Airy structure was studied. The Airy minimum in inelastic scattering is found to be shifted backward compared with that in elastic scattering.
• Refractive effects and Airy structure in inelastic O-16+C-12 rainbow scattering

  S. Ohkubo, Y. Hirabayashi, A. A. Ogloblin, Yu. A. Gloukhov, A. S. Dem'yanova, W. H. Trzaska

  PHYSICAL REVIEW C 90 (6) 064617-1 - 064617-6 2469-9985 2014/12 [Refereed][Not invited]
   

  Inelastic O-16 + C-12 rainbow scattering to the 2(+) (4.44 MeV) state of C-12 was measured at the incident energies, E-L = 170, 181, 200, 260, and 281 MeV. A systematic analysis of the experimental angular distributions was performed using the coupled-channels method with an extended double folding potential derived from realistic wave functions for C-12 and O-16 calculated with a microscopic alpha cluster model and a finite-range density-dependent nucleon-nucleon force. The coupled-channels analysis of the measured inelastic-scattering data shows consistently some Airy-like structure in the inelastic-scattering cross sections for the first 2(+) state of C-12, which is somewhat obscured and still not clearly visible in the measured data. The Airy minimum was identified from the analysis and the systematic energy evolution of the Airy structure was studied. The Airy minimum in inelastic scattering is found to be shifted backward compared with that in elastic scattering.
• Similarity between nuclear rainbow and meteorological rainbow: Evidence for nuclear ripples

  S. Ohkubo, Y. Hirabayashi

  Physical Review C - Nuclear Physics 89 (6) 1089-490X 2014/06/27 [Refereed][Not invited]
   

  We present evidence for the nuclear ripples superimposed on the Airy structure of the nuclear rainbow, which is similar to the meteorological rainbow. The mechanism of the nuclear ripples is also similar to that of the meteorological rainbow, which is caused by the interference between the externally reflective waves and refractive waves. The nuclear ripple structure was confirmed by analyzing the elastic angular distribution in O16+C12 rainbow scattering at EL=115.9 MeV using the coupled channels method by taking account of coupling to the excited states of C12 and O16 with a double folding model derived from a density-dependent effective nucleon-nucleon force with realistic wave functions for C12 and O16. The coupling to the excited states plays the role of creating the external reflection. © 2014 American Physical Society.
• Similarity between nuclear rainbow and meteorological rainbow: Evidence for nuclear ripples

  S. Ohkubo, Y. Hirabayashi

  PHYSICAL REVIEW C 89 (6) 061601-1 - 061601-5 2469-9985 2014/06 [Not refereed][Not invited]
   

  We present evidence for the nuclear ripples superimposed on the Airy structure of the nuclear rainbow, which is similar to the meteorological rainbow. The mechanism of the nuclear ripples is also similar to that of the meteorological rainbow, which is caused by the interference between the externally reflective waves and refractive waves. The nuclear ripple structure was confirmed by analyzing the elastic angular distribution in O-16 + C-12 rainbow scattering at E-L = 115.9 MeV using the coupled channels method by taking account of coupling to the excited states of C-12 and O-16 with a double folding model derived from a density-dependent effective nucleon-nucleon force with realistic wave functions for C-12 and O-16. The coupling to the excited states plays the role of creating the external reflection.
• Evidence for a secondary bow in Newton's zero-order nuclear rainbow

  S. Ohkubo, Y. Hirabayashi

  Physical Review C - Nuclear Physics 89 (5) 1089-490X 2014/05/08 [Refereed][Not invited]
   

  Rainbows are generally considered to be caused by static refraction and reflection. A primary and a secondary rainbow appear due to refraction and internal reflection in a raindrop as explained by Newton. The quantum nuclear rainbow, which is generated by refraction in the nucleus droplet, only has a "primary" rainbow. Here we show for the first time evidence for the existence of a secondary nuclear rainbow generated dynamically by coupling to an excited state without internal reflection. This has been demonstrated for experimental O16+C12 scattering using the coupled channel method with an extended double folding potential derived from microscopic realistic wave functions for C12 and O16. © 2014 American Physical Society.
• Evidence for a secondary bow in Newton's zero-order nuclear rainbow

  S. Ohkubo, Y. Hirabayashi

  PHYSICAL REVIEW C 89 (5) 051601(R)-1 - 051601(R)-5 2469-9985 2014/05 [Refereed][Not invited]
   

  Rainbows are generally considered to be caused by static refraction and reflection. A primary and a secondary rainbow appear due to refraction and internal reflection in a raindrop as explained by Newton. The quantum nuclear rainbow, which is generated by refraction in the nucleus droplet, only has a "primary" rainbow. Here we show for the first time evidence for the existence of a secondary nuclear rainbow generated dynamically by coupling to an excited state without internal reflection. This has been demonstrated for experimental O-16 + C-12 scattering using the coupled channel method with an extended double folding potential derived from microscopic realistic wave functions for C-12 and O-16.
• Sigma NN quasibound states in He-3( K-, pi -/+) reactions at 600 MeV/c

  Toru Harada, Yoshiharu Hirabayashi

  PHYSICAL REVIEW C 89 (5) 054603-1 - 054603-16 0556-2813 2014/05 [Refereed][Not invited]
   

  We theoretically demonstrate the inclusive and semiexclusive spectra in the He-3( K-, pi(+)) reactions at 600 MeV/c (4 degrees) within a distorted-wave impulse approximation, using a coupled (2N - A) + (2N - Sigma) model with a spreading potential. We present the possible existence of the Sigma NN quasibound state with J(pi) = 1/2(+), T similar or equal to 1 near the Sigma threshold, predicted by a 2N - Y folding-model potential derived from YN g-matrices. The result shows that a signal of the 3(Sigma) He quasibound state is clearly confirmed near the Sigma threshold in the pi(-) spectrum, whereas a peak of the 3(Sigma)n n quasibound state is rather reduced in the pi(+) spectrum owing to the interference effects caused by the (3)S1- (1)S0 admixture in the NN pair. The mechanism of Sigma production for these spectra and charge symmetry breaking effects are also discussed.
• Microscopic calculations of cross sections for 6,7Li + n reactions

  D. Ichinkhorloo, M. Aikawa, S. Chiba, Y. Hirabayashi, K. Kato

  Proceedings of the 5th International Conference on Contemporary Physics 142  2013/12 [Not refereed][Not invited]
  
• Hypernuclear Lambda Lambda production by (K-, K+) reactions and the Lambda Lambda-Xi mixing in hypernuclei

  Toru Harada, Yoshiharu Hirabayashi, Atsushi Umeya

  NUCLEAR PHYSICS A 914 85 - 90 0375-9474 2013/09 [Refereed][Not invited]
   

  We theoretically study production of a Lambda Lambda hypernucleus C-16(Lambda Lambda) in a (K-, K+) reaction on an O-16 target at pK(-) = 1.8 GeV/c, within a distorted-wave impulse approximation. The calculated spectrum provides promising peaks of the Lambda Lambda bound and excited states of C-16(Lambda Lambda) in a one-step mechanism K- p -> K+ Xi(-) via Xi(-) doorways caused by a Xi(-) p -> Lambda Lambda coupling, rather than in a two-step mechanism as K- p -> pi(0) Lambda followed by pi(0) p -> K+ Lambda. The cross sections and Xi(-) admixture probabilities are discussed in terms of the Xi N-Lambda Lambda coupling in the nucleus. (C) 2013 Elsevier B.V. All rights reserved.
• Production Spectra of the ΣNN Quasibound States in 3He(K-, π∓) Reactions

  Toru Harada, Yoshiharu Hirabayashi

  Few-Body Systems 54 (7-10) 1205 - 1209 0177-7963 2013/08 [Refereed][Not invited]
   

  We theoretically demonstrate the inclusive and semiexclusive spectra in the 3He (K -, π ∓) reactions at 600 MeV/c (4°) within a distorted-wave impulse approximation, using a coupled (2N - Λ) + (2N - Σ) model with a spreading potential. It is shown that a signal of a 3ΣHe quasibound state is clearly observed near the Σ threshold in the π - spectrum, whereas a peak of a 3Σn quasibound state is relatively reduced in the π + spectrum. The mechanism of Σ production for these spectra is discussed. © 2013 Springer-Verlag Wien.
• Unification of Airy structure in inelastic alpha+O-16 scattering and alpha-cluster structure with core excitation in Ne-20

  Y. Hirabayashi, S. Ohkubo

  PHYSICAL REVIEW C 88 (1) 014314-1 - 014314-6 0556-2813 2013/07 [Refereed][Not invited]
   

  The Airy structure of the nuclear rainbow and prerainbow in inelastic and elastic alpha + O-16 scattering is studied with the coupled channel method using a folding potential derived from the microscopic wave functions of O-16. The theoretical calculations reproduce the characteristic energy evolution of the Airy minimum of the experimental angular distributions. The energy levels with alpha-cluster structure in Ne-20 are reproduced well using the potentials determined from the analysis of scattering. It is shown that the emergence of the K = 0(3)(+) alpha-cluster band with core excitation at 7.19 MeV in Ne-20 is intimately related to the emergence of the prerainbow and rainbow in inelastic scattering to the O-16(0(2)(+)). It is found that the alpha-cluster states with core excitation, the prerainbow and the rainbow in inelastic scattering are understood in a unified way as well as in the case of elastic scattering.
• Observation of an Airy minimum in elastic and inelastic scattering of 3He from 12C at 50.5 and 60 MeV, and α-particle condensation in 12C

  Sh Hamada, Y. Hirabayashi, N. Burtebayev, S. Ohkubo

  Physical Review C - Nuclear Physics 87 (2) 024311  1089-490X 2013/02/13 [Refereed][Not invited]
   

  Angular distributions for elastic and inelastic scattering of 3He from 12C were measured at energies 50.5 and 60 MeV. The Airy minimum of the prerainbow scattering was clearly observed in the angular distributions for the 02+ (7.65 MeV) state of 12C (Hoyle state). The experimental results were analyzed with a coupled channels method with double folding potentials derived from the microscopic wave functions for the ground 01+, 2+ (4.44 MeV), 3 - (9.64 MeV), and 02+ states. The analysis supports the view that the Hoyle state is a three α particle condensate with a large radius of dilute matter distribution. © 2013 American Physical Society.
• Analysis of 7Li(nn′)7Li* reactions using the continuum-discretized coupled-channels method

  D. Ichinkhorloo, Y. Hirabayashi, K. Kato, M. Aikawa, T. Matsumoto, S. Chiba

  Physical Review C - Nuclear Physics 86 (6) 1089-490X 2012/12/11 [Refereed][Not invited]
   

  We study 7Li(n, n′)7Li* reactions by using the continuum-discretized coupled-channels (CDCC) method with the complex Jeukenne-Lejeune-Mahaux effective nucleon-nucleon interaction. In this study, the 7Li nucleus is described by an α+t cluster model. The calculated elastic cross sections for incident energies between 11.5 and 24.0 MeV show good agreements with experimental data. Furthermore, we calculate the neutron spectra of 7Li ground and excited breakup states measured at selected angular points for incident energies of 11.5 and 18.0 MeV. The results reproduce the observed data systematically. © 2012 American Physical Society.
• Analysis of Li-7(n, n ')Li-7* reactions using the continuum-discretized coupled-channels method

  D. Ichinkhorloo, Y. Hirabayashi, K. Kato, M. Aikawa, T. Matsumoto, S. Chiba

  PHYSICAL REVIEW C 86 (6) 064604-1 - 064604-7 2469-9985 2012/12 [Refereed][Not invited]
   

  We study Li-7(n, n')Li-7* reactions by using the continuum-discretized coupled-channels (CDCC) method with the complex Jeukenne-Lejeune-Mahaux effective nucleon-nucleon interaction. In this study, the Li-7 nucleus is described by an alpha + t cluster model. The calculated elastic cross sections for incident energies between 11.5 and 24.0 MeV show good agreements with experimental data. Furthermore, we calculate the neutron spectra of Li-7 ground and excited breakup states measured at selected angular points for incident energies of 11.5 and 18.0 MeV. The results reproduce the observed data systematically. DOI: 10.1103/PhysRevC.86.064604
• Angular distributions of elastic scattering of Sigma(-) hyperons from nuclei and the Sigma-nucleus potentials

  Toru Harada, Yoshiharu Hirabayashi

  PHYSICAL REVIEW C 86 (1) 014606  0556-2813 2012/07 [Refereed][Not invited]
   

  We theoretically investigate the elastic scattering of 50-MeV Sigma(-) hyperons from Si-28 and Pb-208 in order to clarify the radial distribution of Sigma-nucleus (optical) potentials. The angular distributions of differential cross sections are calculated using several potentials that can explain experimental data of the Sigma(-) atomic x-ray and (pi(-), K+) reaction spectra simultaneously. The magnitude and oscillation pattern of the angular distributions are understood by the use of nearside/farside decompositions of their scattering amplitudes. It is shown that the resultant angular distributions provide a clue to discriminating among the radial distributions of the potentials that have a repulsion inside the nuclear surface and an attraction outside the nucleus with a sizable absorption.
• Low-Energy Nuclear Reactions Light Nuclei

  M. Aikawa, Y. Hirabayashi, K. Kato

  Proceedings of the 2011 Symposium on Nuclear Data 107 - 110 2012/07 [Refereed][Not invited]
  
• Systematic description of the Li6(n,n′)6Li *→d+α reactions with the microscopic coupled-channels method

  T. Matsumoto, D. Ichinkhorloo, Y. Hirabayashi, K. Kato, S. Chiba

  Physical Review C - Nuclear Physics 83 (6) 064611  1089-490X 2011/06/15 [Refereed][Not invited]
   

  We investigate Li6(n,n′)6Li *→d+α reactions by using the continuum-discretized coupled-channels method with the complex Jeukenne-Lejeune-Mahaux effective nucleon-nucleon interaction. In this study, the Li6 nucleus is described by a d+α cluster model. The calculated elastic cross sections for incident energies between 7.47 and 24.0 MeV are in good agreement with experimental data. Furthermore, we show that the neutron spectra for Li6 breakup states measured at selected angular points and incident energies can be also reproduced systematically. © 2011 American Physical Society.
• Systematic description of the Li-6(n,n ')Li-6* -> d plus alpha reactions with the microscopic coupled-channels method

  T. Matsumoto, D. Ichinkhorloo, Y. Hirabayashi, K. Kato, S. Chiba

  PHYSICAL REVIEW C 83 (6) 2469-9985 2011/06 [Refereed][Not invited]
   

  We investigate Li-6(n, n')Li-6* -> d + alpha reactions by using the continuum-discretized coupled-channels method with the complex Jeukenne-Lejeune-Mahaux effective nucleon-nucleon interaction. In this study, the Li-6 nucleus is described by a d + alpha cluster model. The calculated elastic cross sections for incident energies between 7.47 and 24.0 MeV are in good agreement with experimental data. Furthermore, we show that the neutron spectra for Li-6 breakup states measured at selected angular points and incident energies can be also reproduced systematically.
• ALPHA-PARTICLE CONDENSATION IN O-16

  S. Ohkubo, Y. Hirabayashi

  INTERNATIONAL JOURNAL OF MODERN PHYSICS E-NUCLEAR PHYSICS 20 (4) 880 - 884 0218-3013 2011/04 [Refereed][Not invited]
   

  The existence of a rotational band with the alpha+C-12(0(2)(+)) cluster structure is demonstrated near the four-alpha threshold of O-16 in agreement with experiment. A drastic reduction of the moment of the inertia of the 0(+) state at 15.1 MeV suggests that it is superfluid with four alpha-particle condensation. The rotational excitation of the condensate in O-16 is discussed.
• Analysis of n + 6Li reactions using the continuum-discretized coupled-channels method

  Dagvadorj Ichinkhorloo, Takuma Matsumoto, Yoshiharu Hirabayashi, Kiyoshi Kato, Satoshi Chiba

  Journal of Nuclear Science and Technology 48 (11) 1357 - 1360 0022-3131 2011 [Refereed][Not invited]
   

  The n + 6Li reactions are important not only from the basic interest but also from the application point of view. We study 6Li breakup reactions at incident neutron energies of 11.5, 14.1, and 18.0MeV applying a d + α cluster model to 6Li and using the continuum-discretized coupled-channels (CDCC) approach. At the present energies, our calculation well reproduces the experimental data. This successful result indicates the reliability of the CDCC approach based on the cluster model to the nuclear reaction evaluation of light nuclear reactions. © 2011 Atomic Energy Society of Japan.
• Li-6+n Reactions in the Continuum Discretized Coupled Channels method

  D. Ichinkhorloo, T. Matsumoto, Y. Hirabayashi, K. Kato, S. Chiba

  SECOND INTERNATIONAL ULAANBAATAR CONFERENCE ON NUCLEAR PHYSICS AND APPLICATIONS 1342 102 - 105 0094-243X 2011 [Refereed][Not invited]
   

  The few-body, especially three-body, problem is still an open (and therefore interesting) subject in nuclear physics, and has been studied intensively by various theoretical frameworks. The n + Li-6 reactions are important not only from the basic interest but also from the application point of view. The Li-6 nucleus is well described by the cluster model such as a + d and a + p + n. Therefore, it is necessary for us to treat the n + Li-6 system with a + d + n and a + p + n + n models. In this work, we study the n + Li-6 inelastic reactions applying the a + d cluster model to Li-6 and using the continuum-discretized coupled-channels approach. We have included elastic and inelastic data at 14.1 MeV neutron incident energies in the calculation. At the present energy, our calculation gives almost good agreement with experimental data.
• Production of doubly strange hypernuclei via Xi(-) doorways in the O-16(K-, K+) reaction at 1.8 GeV/c

  Toru Harada, Yoshiharu Hirabayashi, Atsushi Umeya

  PHYSICS LETTERS B 690 (4) 363 - 368 0370-2693 2010/06 [Refereed][Not invited]
   

  We examine theoretically production of doubly strange hypernuclei, (Xi)-C-16 and C-16(Lambda Lambda), in double-charge exchange O-16(K-, K+) reactions using a distorted-wave impulse approximation. The inclusive K+ spectrum at the incident momentum p(K)- = 1.8 GeV/c and scattering angle theta(lab) = 0 degrees is estimated in a one-step mechanism, K(-)p -> K+Xi(-) via Xi(-) doorways caused by a Xi(-)p-Lambda Lambda coupling. The calculated spectrum in the Xi(-) bound region indicates that the integrated cross sections are on the order of 7-12 nb/sr for significant 1(-) excited states with C-14(0(+) ,2(+)) circle times s(Lambda)p(Lambda) configurations in C-16(Lambda Lambda) via the doorway states of the spin-stretched N-15(1/2(-), 3/2(-)) circle times s(Xi-) in (Xi)-C-16 due to a high momentum transfer q(Xi)- similar or equal to 400 MeV/c. The Xi(-) admixture probabilities of these states are on the order of 5-9%. However, populations of the 0(+) ground state with C-14(0(+)) circle times s(Lambda)(2), and the 2(+) excited state with C-14(2(+)) circle times s(Lambda)(2) are very small. The sensitivity of the spectrum on the Xi N-Lambda Lambda coupling strength enables us to extract the nature of Xi N-Lambda Lambda dynamics in nuclei, and the nuclear (K-, K+) reaction can extend our knowledge of the S = -2 world. (C) 2010 Elsevier B.V. All rights reserved.
• alpha-particle condensate states in O-16

  S. Ohkubo, Y. Hirabayashi

  PHYSICS LETTERS B 684 (2-3) 127 - 131 0370-2693 2010/02 [Refereed][Not invited]
   

  The existence of a rotational hand with the alpha + C-12(0(2)(+)) Cluster structure, in which three alpha particles in C-12(0(2)(+)) are locally condensed, is demonstrated near 2 the four-alpha threshold of O-16 in agreement with experiment. This is achieved by Studying structure and scattering for the alpha + C-12(0(2)(+)) system in a unified way. A drastic reduction (quenching) of the moment of the inertia of the 0(+) state at 15.1 MeV just above the four-alpha threshold in O-16 suggests that it Could be a candidate for the superfluid state in alpha-particle condensation. (C) 2010 Elsevier B.V. All rights reserved.
• Coulomb-assisted Sigma(-)-nucleus bound states in the (K-, pi(+)) reaction

  Toru Harada, Yoshiharu Hirabayashi

  NUCLEAR PHYSICS A 829 (1-2) 100 - 125 0375-9474 2009/10 [Refereed][Not invited]
   

  We study a production of Coulomb-assisted Sigma(-)-nucleus bound states by nuclear (K-, pi(+)) reactions within a distorted-wave impulse approximation, so as to examine several types of the Sigma-nucleus potentials that are consistent with the available Sigma(-) atomic X-ray data and nuclear (pi(-), K+) data. We theoretically demonstrate the inclusive (K-, pi(+)) spectra of the Sigma(-) unstable bound states on Si-28, Ni-58, and Pb-208 targets at incident K- lab momenta p(K) = 400-800 MeV/c. The results show that the near-recoilless (K-, pi(+)) reaction on the Ni-58 target gives a clear candidate to confirm properties of the Sigma-nucleus potentials having a repulsion inside the nuclear surface and an attraction outside the nucleus with a sizable absorption, whereas details of the repulsion of the potential at the nuclear center cannot be determined by the inclusive spectra. This is a promising attempt to extract properties of the Sigma-nucleus potential in the nucleus at forthcoming J-PARC experiments, as a full complement to the analyses of the Sigma(-) atomic and (pi(-), K+) data. (C) 2009 Elsevier B.V. All rights reserved.
• Feasibility of extracting a Sigma(-) admixture probability in the neutron-rich Li-10(Lambda) hypernucleus

  T. Harada, A. Umeya, Y. Hirabayashi

  PHYSICAL REVIEW C 79 (1) 014603  0556-2813 2009/01 [Refereed][Not invited]
   

  We theoretically examine production of the neutron-rich Li-10(Lambda) hypernucleus by a double-charge exchange (pi(-), K+) reaction on a B-10 target with distorted-wave impulse approximation calculations. We calculate the inclusive spectrum at the incident momentum 1.20 GeV/c by a one-step mechanism pi(-) p -> K+Sigma(-) via Sigma(-) doorways caused by a Sigma(-) p <-> Lambda n coupling. The resultant spectrum can explain the magnitude of the recent experimental data, so that the Sigma(-) admixture probability in Li-10(Lambda) is found to be of the order of 10(-1)%. The (pi-, K+) reaction provides the ability to extract properties of wave functions with Lambda-Sigma coupling effects in neutron-rich nuclei, as well as the reaction mechanism.
• Alpha particle condensation and nuclear rainbow scattering

  S. Ohkubo, Y. Hirabayashi

  Journal of Physics: Conference Series 111 (1) 012014-1 - 012014-4 1742-6596 2008/05/01 [Refereed][Not invited]
   

  It is shown that a dilute property of an a particle condensate can be seen in the Airy structure of nuclear rainbow and prerainbow scattering. The dilute property of the Hoyle state of 12C with a developed α cluster structure is discussed by studying refractive 3He+ 12C and α + 12C scattering. © 2008 IOP Publishing Ltd.
• Evidence for higher nodal band states with (3)He cluster structure in (19)Ne and prerainbows in (3)He+(16)O scattering

  S. Ohkubo, Y. Hirabayashi

  PHYSICAL REVIEW C 77 (4) 041303  0556-2813 2008/04 [Refereed][Not invited]
   

  The existence of a higher nodal band state with a (3)He cluster structure, i.e., a vibrational mode in which the intercluster relative motion is excited in (19)Ne in addition to those with the alpha cluster structure in (20)Ne and the (16)O cluster structure in (32)S, is suggested, which reinforces the importance of the concept of (3)He clustering in nuclei. This conclusion was reached by investigating (3)He scattering from (16)O in a wide range of incident energies and prerainbow oscillations.
• Prerainbow Oscillation in 3He Scattering from the Hoyle State of 12C and Alpha Particle

  S. OHKUBO, Y. HIRABAYASHI

  Proc. Int. Symp. Physics of Unstable Nuclei 92 - 97 2008 [Refereed][Not invited]
  
• Development of experimental nuclear reaction data file for astrophysics

  N. Otuka, M. Aikawa, Y. Hirabayashi, A. Ohnishi, K. Kato

  ORIGIN OF MATTER AND EVOLUTION OF GALAXIES 1016 156 - + 0094-243X 2008 [Refereed][Not invited]
   

  Experimental nuclear reaction data compilation activity in Japan for the NRDF database and international collaboration of experimental nuclear reaction data exchange by the EXFOR format are presented. Recent development of an experimental nuclear reaction data file (NRDF/A) for astrophysics, which is based on the EXFOR compilation, is also introduced. All services are available at http://www.jcprg.org/.
• Alpha particle condensation in C-12 and nuclear rainbow scattering

  S. Ohkubo, Y. Hirabayashi

  FRONTIERS IN NUCLEAR STRUCTURE, ASTROPHYSICS, AND REACTIONS 1012 407 - + 0094-243X 2008 [Refereed][Not invited]
   

  It is shown that the large radius of the Hoyle state of C-12 with a dilute density distribution in an a particle condensate can be clearly seen in the shift of the rainbow angle (therefore the Airy minimum to a larger angle in alpha+C-12 rainbow scattering at the high energy region and prerainbow oscillations in He-3+C-12 scattering at the lower energy region.
• Evidence for strong refraction of He-3 in an alpha-particle condensate

  S. Ohkubo, Y. Hirabayashi

  PHYSICAL REVIEW C 75 (4) 044609  0556-2813 2007/04 [Refereed][Not invited]
   

  We have analyzed He-3 scattering from C-12 at 34.7 and 72 MeV in a coupled channel method with a double folding potential derived from the precise wave functions for the ground 0(+) state and 0(2)(+) (7.65 MeV) Hoyle state, which has been suggested to be an alpha particle condensate. It is found that strong refraction of He-3 in the Hoyle state can be clearly seen in the experimental angular distribution at a low incident energy region as an Airy minimum of the prerainbow oscillations.
• Problems of open publications of educational materials on the Web

  Masayuki AIKAWA, Marie TSUDA, Izumi FUSE, Yoshiharu HIRABAYASHI, Masashi NOSAKA, Tetsu TANABE, Yuichi YAMAMOTO, Kohei WATANABE, Shigeto OKABE

  International Conference on Distance Learning and the Internet 2006 (CD-ROM) 97 - 100 2006/11 [Not refereed][Not invited]
  
• Sigma(-) production spectrum in the inclusive (pi(-), K+) reaction on Bi-209 and the Sigma-nucleus potential

  T Harada, Y Hirabayashi

  NUCLEAR PHYSICS A 767 206 - 217 0375-9474 2006/03 [Refereed][Not invited]
   

  We investigate theoretically the Sigma(-) hypernuclear production by the inclusive (pi(-), K+) reaction on a neutron-excess Bi-209 target in the framework of a distorted wave impulse approximation with an optimal Fermi-averaging for the elementary pi(-) + p -> K+ + Sigma(-) t-matrix. In order to study the Sigma-nucleus potentials constructed with isoscalar and isovector components, we compare the calculated spectra of the Bi-209(pi(-), K+) reaction with the experimental data at KEK, using several Sigma-nucleus (optical) potentials for Sigma(-)-Pb-208 which are determined by fits to the Sigma(-) atomic X-ray data. Our analysis confirms that the potentials having a repulsion inside the nuclear surface and an attraction outside the nucleus with a sizable absorption, can well reproduce the data. But it is still difficult to discriminate among the radial distributions of these potentials inside the heavy nucleus. The contribution of the isovector component in the potential is not determined uniquely by the Bi-209(pi(-), K+) spectrum. (c) 2006 Elsevier B.V. All rights reserved.
• Is the Sigma-nucleus potential for Sigma(-) atoms consistent with the Si-28(pi(-), K+) data?

  T Harada, Y Hirabayashi

  NUCLEAR PHYSICS A 759 (1-2) 143 - 169 0375-9474 2005/09 [Refereed][Not invited]
   

  In order to examine whether the Sigma-nucleus potential for Sigma(-) atoms can explain the experimental (pi(-), K+) data or not, we evaluate Sigma(-) hypernuclear production by the (pi(-), K+) reaction on a (28)si target, in the framework of a distorted-wave impulse approximation with an optimal Fermi-averaging for the elementary pi(-) + p -> K+ + Sigma(-) t-matrix. Inclusive K+ spectra of the Si-28(pi(-), K+) reaction are calculated with several E-nucleus (optical) potentials for Sigma(-)-Al-27 which are determined by fits to the Sigma- atomic X-ray data, and the properties of these potentials are tested in detail by comparing the calculated spectra with the (pi(-) K+) experimental data at KEK. The results show that the potentials having a repulsion inside the nuclear surface and an attraction outside the nucleus with a sizable absorption, can reproduce the Si-28(pi(-), K+) data very well; the optimal Fermi-averaging for the pi(-) + P -> K+ + Sigma(-) reaction also gives a good description of the energy-dependence in the Sigma(-) quasi-free spectrum. This is the first successful attempt to explain simultaneously the Sigma-atomic X-ray data and the (pi(-), K+) reaction. (c) 2005 Elsevier B.V. All rights reserved.
• Σ-ポテンシャルとΣ-生成スペクトル(バリオン力とバリオン物質,研究会報告)

  原田 融, 平林 義治

  素粒子論研究 素粒子論グループ 素粒子論研究 編集部 111 (4) D45 - D46 0371-1838 2005
• Optimal Fermi-averaging for the pi+n -> K++Lambda t-matrix in Lambda-hypernuclear production from (pi(+), K+) reactions

  T Harada, Y Hirabayashi

  NUCLEAR PHYSICS A 744 323 - 343 0375-9474 2004/11 [Refereed][Not invited]
   

  In order to describe A quasi-free production spectra from (pi(+), K+) reactions, we propose an optimal Fermi-averaging for the elementary pi(+) + n --> K+ + Lambda t-matrix in a nucleus under the on-energy-shell condition. We calculate these quasi-free spectra for (pi(+), K+) reactions on a C-12 target at p(pi) = 1.20 GeV/c and 1.05 GeV/c, and compare them with experimental data. The results show that the shape and magnitude of the spectra can explain the data, because the optimal Fermi-averaged t-matrix gives a good description of the energy-dependence in the spectra. The Lambda quasi-free spectra on a heavier Si-28 target are also discussed. (C) 2004 Elsevier B.V. All rights reserved.
• Bose-Einstein condensation of alpha particles and Airy structure in nuclear rainbow scattering

  S Ohkubo, Y Hirabayashi

  PHYSICAL REVIEW C 70 (4) 041602  0556-2813 2004/10 [Refereed][Not invited]
   

  It is shown that the dilute density distribution of alpha particles in nuclei can be observed in the Airy structure in nuclear rainbow scattering. We have analyzed alpha+C-12 rainbow scattering to the 0(2)(+) (7.65 MeV) state of C-12 in a coupled-channel method with the precise wave functions for C-12. It is found that the enhanced Airy oscillations in the experimental angular distributions for the 0(2)(+) state is caused by the dilute density distribution of this state in agreement for the idea of Bose-Einstein condensation of the three alpha particles.
• Multicluster configuration in highly excited states of 24Mg

  M. Ito, Y. Hirabayashi, Y. Sakuragi

  Physical Review C - Nuclear Physics 66 (3) 343071 - 3430718 0556-2813 2002/09/01 [Refereed][Not invited]
   

  The nuclear structure of 24Mg with 12C+ 3 α and 3 α+ 3 α configurations, existing at an extremely highly-excited energy domain is studied by the microscopic coupled-channels (MCC) calculation based on the double-folding interactions using 3 α-RGM wave functions of 12C and a realistic nucleon-nucleon interaction called DDM3Y. The dinuclear 12C+ 12C configuration of 24Mg, corresponding to the so-called "higher-energy molecular resonances," is also investigated by the same MCC framework. The MCC calculation predicts the existence of three kinds of the molecular bands having 3 α+ 3 α, 12C+ 3 α, and 12C+ 12C structures around the excitation energy of about 40 MeV with respect to the ground state of 24Mg. The channel coupling among the 3 α states in each 12C plays very important roles for the formation of the 12C+3 α and 3 α+3 α molecular bands. It is found that the populations of the 12Cg.s.+12Cg.s., 12Cg.s. +12C(02 +), and 12C(02 +) +12C(02 +) channels are very small in the individual molecular bands with 12C+ 12C, 12C+ 3 α, and 3 α+ 3 α configurations, respectively. The reaction mechanism for the inelastic scattering leading to the 12Cg.s. + 12C(02 +) and 12C(02 +) 12C(02 +) excitation channels is also investigated in relation to the obtained three kinds of the molecular bands. The result suggests that the inelastic scattering to the 12C(02 +) + 12C(02 +) [12Cg.s.+12C(02 +)] channel can be interpreted in terms of weak transitions from the 12Cg.s. + 12Cg.s. component of the 12C+ 12C molecular bands to the 12C(02 +)+ 12C(02 +) [ 12Cg.s. + 12C(02 +)] component of the multicluster 3 ́+3 α (12C+3 α) molecular bands. All the results are discussed in connection with the band crossing model which was proposed in describing the higher-energy molecular resonance with dinuclear configuration as well as the resonances observed in the 12C(02 +)+ 12C(02 +) and 12Cg.s.+12C(02 +) exit channels.
• Alpha scattering from nonclosed shell nucleus C-12 and alpha-nucleus interaction

  Y Hirabayashi, S Ohkubo

  PHYSICS OF ATOMIC NUCLEI 65 (4) 683 - 688 1063-7788 2002/04 [Refereed][Not invited]
   

  In order to understand the alpha-nucleus interactions for the alpha + C-12 similar to alpha + O-16 systems systematically, a scattering from 12C is studied in a microscopic coupled-channel model using a folding potential and realistic microscopic wave functions of 12C. The experimental angular distributions of elastic and inelastic scattering to the 2(+) (4.43 MeV), 3(-) (9.64 MeV), and 0(2)(+) (7.66 MeV) states in the range of E-alpha = 41-172.5 MeV are analyzed. (C) 2002 MAIK "Nauka/Interperiodica".
• New distorted-wave impulse approximation calculation for inelastic scattering of deuterons at intermediate energies with the sudden approximation approach

  Y. Hirabayashi, T. Suzuki, M. Tanifuji

  Physical Review C - Nuclear Physics 64 (5) 546051 - 5460517 1089-490X 2001 [Refereed][Not invited]
   

  We perform a distorted-wave impulse approximation calculation of inelastic scattering of deuterons by nuclei using effective interactions in the framework of the sudden approximation at Ed=400 MeV. Cross sections and spin observables are expressed in terms of amplitudes for the corresponding nucleon-nucleus scattering. The calculation is examined for the excitation of 12C to the 2+ (2.44 MeV), 3- (9.64 MeV), and 1+ (12.71 MeV) states and is found to give a reasonable description for most of the observables. Some discrepancies are found for the transition leading to the 1+ state, suggesting the limitation of the applicability of the effective interaction. Contributions of the deuteron D state are studied. Relations between the deuteron-nucleus and proton-nucleus scattering observables are found and are studied against existing data.
• Properties of microscopic nucleus-nucleusinteraction for molecular resonance formation in 12C + 12C and 3α+3α systems

  M. Ito, Y. Sakuragi, Y. Hirabayashi

  Physical Review C 63 (6) 064303  0556-2813 2001/01 [Refereed][Not invited]
  
• Properties of microscopic nucleus-nucleus interaction for molecular resonance formation in [Formula Presented] and [Formula Presented] systems

  M. Ito, Y. Sakuragi, Y. Hirabayashi

  Physical Review C - Nuclear Physics 63 (6) 16  1089-490X 2001 [Refereed][Not invited]
   

  Properties of microscopic interaction potentials between two [Formula Presented] nuclei are discussed in connection with the formation of [Formula Presented] and [Formula Presented] molecular resonances. The nucleus-nucleus interactions are calculated by the double-folding procedure based on a realistic nucleon-nucleon interaction (DDM3Y) and microscopic [Formula Presented] transition densities calculated from 3α-RGM wave functions. The interaction potential can be written as the sum of the monopole part obtained from the monopole density and the multiple parts generated from the quadrupole component of the density. We discuss the role of the monopole and multipole parts of the potential separately. It is shown that the multipole part is very strong in the channels with [Formula Presented] structure and the energy positions of the [Formula Presented] molecular bands generated by the monopole potential are largely modified. The effect is moderate but non-negligible on the molecular bands with the [Formula Presented] dinuclearlike structure and largely modifies the band crossing diagram between the elastic and aligned-inelastic molecular bands. The channel coupling effect among the [Formula Presented] channels, namely, the elastic channel and the single- and mutual-[Formula Presented] excitation channels is also investigated. Due to the strong coupling between the ground and [Formula Presented] states of [Formula Presented] the resonance wave functions obtained by the coupled-channel calculation have an additional radial node compared with those of the single-channel resonances. All the results are discussed in connection with the band crossing model which was believed to be successful in describing the [Formula Presented] molecular resonances. © 2001 The American Physical Society.
• DWIA calculations for inelastic scattering of deuterons at E-d=400MeV

  Y Hirabayashi, T Suzuki, M Tanifuji

  SPIN 2000 570 659 - 663 0094-243X 2001 [Refereed][Not invited]
   

  A new type of DWBA calculation for inelastic scattering of deuterons is formulated based on the sudden approximation. Cross section and polarization observables are expressed in terms of the scattering matrices for the constituent nucleons with the same target transitions. The formalism is applied for an excitation of isoscalar states in C-12 using DWBA amplitudes for the nucleon-nucleus scattering. Excellent agreement with existing data has been obtained for natural parity transitions, while some discrepancies remain for unnatural parity ones. The latter could be related to the choice of the effective nucleon-nucleon interaction. A relationship between observables for deuteron-nucleus and proton-nucleus scattering was found, which are well satisfied in the existing data. Details will be given elsewhere [1].
• Channel coupling effects in resonant breakup of 42 MeV Li-7 with Ni-58 target

  D Gupta, C Samanta, A Chatterjee, K Rusek, Y Hirabayashi

  JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS 26 (6) L81 - L86 0954-3899 2000/06 [Refereed][Not invited]
   

  The angular distribution of the 42 MeV Li-7 sequential breakup (via 7/2(-), 4.63MeV state) with Ni-58 target, measured beyond the grazing angle, is presented. Analyses of both elastic scattering and sequential breakup are carried out in a continuum-discretized coupled channel framework. In sequential breakup, contributions from multi-step processes are found to be significant at this low incident energy.
• Relation Between (p,p') and (d,d') on 12C in the Sudden Approximation

  Y. Hirabayashi, T. Suzuki, M. Tanifuji

  Proceedings RCNP-TMU Sympsium SPIN IN NUCLEAR AND HADRONIC REACTION 56 - 61 2000 [Refereed][Not invited]
  
• Microscopic coupled-channel study of C-12+C-12 resonance reactions

  M Ito, Y Sakuragi, Y Hirabayashi

  FEW-BODY PROBLEMS IN PHYSICS '99 12 137 - 140 0177-8811 2000 [Refereed][Not invited]
   

  Resonance structures recently observed in the C-12+C-12 inelastic scattering leading to multi-cluster exit channels, having 3 alpha+C-12 and 3 alpha +3 alpha configuration, are studied theoretically by the microscopic coupled-channel calculation. We use the microscopic 3 alpha: cluster model wave functions of C-12 and the density dependent nucleon-nucleon interaction. The results of CC calculation consistently reproduce the resonance structures of the excitation functions not only in the multi-cluster exit channels but also in those of the well-known exit channels having di-nucleus configuration. The reaction mechanism leading to the resonance formation in the multi-cluster channels is also discussed in some details in connection to the various molecular bands of C-12+C-12 system existing at more than 40 MeV excitation energies of Mg-24.
• Microscopic coupled-channel study of heavy-ion resonances in multi-cluster exit channels

  Y Sakuragi, M Ito, M Katsuma, M Takashina, Y Kudo, Y Hirabayashi, S Okabe, Y Abe

  PROCEEDINGS OF THE 7TH INTERNATIONAL CONFERENCE ON CLUSTERING ASPECTS OF NUCLEAR STRUCTURE AND DYNAMICS 138 - 142 2000 [Refereed][Not invited]
   

  Heavy-ion resonances recently discovered in nuclear collisions of C-12+C-12 and O-16+O-16 systems leading to multi-cluster exit channels, C-12+C-12 --> 3 alpha+C-12, 3 alpha +3 alpha, 2 alpha+O-16 and O-16+O-16 --> (alpha+C-12)+O-16, (alpha+C-12)+(alpha+C-12), are studied theoretically by the coupled-channel (CC) and coupled-channel Born approximation (CCBA) calculations using microscopic cluster-model wave functions of the colliding nuclei, C-12 and O-16, and nucleus-nucleus interactions based on the realistic G-matrix interaction. These resonance states correspond to highly excited states of the compound systems, Mg-24 and S-32 nuclei, at excitation energies more than 40 similar to 55 MeV. The the microscopic CC and CCBA calculations well reproduce the characteristic features of these new resonance states.
• Dynamic polarization potential of 12C + 12C system at molecular-resonance energies

  M. Ito, Y. Sakuragi, Y. Hirabayashi

  The European Physical Journal A 5 (4) 373 - 383 1434-6001 1998/08 [Refereed][Not invited]
  
• alpha-cluster structure of Ti-44 in core-excited alpha+Ca-40 model

  S Ohkubo, Y Hirabayashi, T Sakuda

  PHYSICAL REVIEW C 57 (5) 2760 - 2762 0556-2813 1998/05 [Refereed][Not invited]
   

  It is shown that all the rotational bands in Ti-44 at low and high excitation energies can be well explained in an alpha-cluster model in which the alpha-like excitation of the core, Ca-40, is incorporated by employing density-dependent M3Y (DDM3Y) double folding potentials. [S0556-2813(98)03105-7].
• 3 alpha+3 alpha structure of highly excited states in Mg-24

  M Ito, Y Sakuragi, Y Hirabayashi, Y Abe

  PROCEEDINGS OF THE XVII RCNP INTERNATIONAL SYMPOSIUM ON INNOVATIVE COMPUTATIONAL METHODS IN NUCLEAR MANY-BODY PROBLEMS 229 - 231 1998 [Refereed][Not invited]
   

  We have analysed the highly-excited states of Mg-24 around 30 MeV above the 6 alpha threshold in a microscopic coupled-channels framework and we have identified several rotational bands having a 3 alpha+3 alpha structure in this energy region, which cross with the other kind of rotational bands having C-12+C-12 structure. The relation of these band structures and the resonance recently observed in the C-12(O-2(+))+C-12(O-2(+)) reaction is discussed.
• Heavy-ion resonance and multi-cluster states in highly excited nuclei

  Y Sakuragi, M Ito, M Katsuma, M Takashina, Y Hirabayashi, S Okabe, Y Abe

  PROCEEDINGS OF THE XVII RCNP INTERNATIONAL SYMPOSIUM ON INNOVATIVE COMPUTATIONAL METHODS IN NUCLEAR MANY-BODY PROBLEMS 196 - 204 1998 [Refereed][Not invited]
   

  Heavy-ion resonances recently observed in the collisions of C-12+C-12 and O-16+O-16 systems leading to the multi-cluster exit channels are studied theoretically. The excitation of C-12 and O-16 to the states having the 3 alpha and alpha+C-12 cluster configurations are explicitly taken into account by the coupled-channels (CC) calculation using microscopic form factors based on the microscopic cluster-model wave functions. The calculation reproduces the essential features of the resonances observed in the multi-cluster exit channels surprisingly well. A prominent resonance structure is also predicted in the Be-8+O-16 system by the CC calculation with the Be-8 excitations treated explicitly, which suggests a possible explanation of the resonances observed in the C-12+C-12 --> B-8+O-16 alpha-transfer reactions.
• [Formula Presented]-cluster structure of [Formula Presented] in core-excited [Formula Presented] model

  S. Ohkubo, Y. Hirabayashi, T. Sakuda

  Physical Review C - Nuclear Physics 57 (5) 2760 - 2762 1089-490X 1998 [Refereed][Not invited]
   

  It is shown that all the rotational bands in [Formula Presented] at low and high excitation energies can be well explained in an [Formula Presented]-cluster model in which the [Formula Presented]-like excitation of the core, [Formula Presented], is incorporated by employing density-dependent M3Y (DDM3Y) double folding potentials. © 1998 The American Physical Society.
• Breakup effect on the Li-6 elastic scattering from Si-28 at E/A=35 and 53 MeV

  Y Sakuragi, M Ito, Y Hirabayashi, C Samanta

  PROGRESS OF THEORETICAL PHYSICS 98 (2) 521 - 525 0033-068X 1997/08 [Refereed][Not invited]
   

  The effect of projectile breakup on the Li-6 elastic scattering from Si-28 at E/A = 35 and 53 MeV is investigated with the continuum-discretized coupled-channels method using the double-folding model interactions based on the density-dependent M3Y (DDM3Y) interaction. It is shown that the breakup effect is still important and of a repulsive nature at these incident energies.
• Breakup of 30 MeV/u-O-16 in nuclear and Coulomb fields of Sn-120 and Pb-208 nuclei

  D OKelly, T Botting, B Hurst, RP Schmitt, YW Lui, Y Hirabayashi, S Okabe, Y Sakuragi, H Utsunomiya, T Yamagata, M Ohta

  PHYSICS LETTERS B 393 (3-4) 301 - 306 0370-2693 1997/02 [Refereed][Not invited]
   

  Coincidence measurements of alpha-C-12 pairs collinearly emitted in the breakup of 30 MeV/u- O-16 incident on Pb-208 and Sn-120 were performed with a two detector system set up along the focal plane of a magnetic spectrograph. Double differential cross sections for sequential breakup via the 2(2)(+) and 2(3)(+) states in O-16 were analyzed within the framework of coupled-channels (CC) calculations which incorporated microscopic alpha-C-12 cluster model wave functions for bound and unbound states of O-16, The experimental data are satisfactorily reproduced by the CC calculations to within a factor of two. The results are discussed in terms of the interference between nuclear- and Coulomb-breakup amplitudes.
• Energy Dependence of 6Li-Nucleus Interactions at Intermediate Energies

  C. Samanta, Y. Sakuragi, M. Ito, Y. Hirabayashi

  Journal of Physics G 23 1697 - 1705 1997 [Not refereed][Not invited]
  
• 3-ALPHA+3-ALPHA AND 3-ALPHA+C-12 CONFIGURATIONS IN MG-24

  Y HIRABAYASHI, Y SAKURAGI, Y ABE

  PHYSICAL REVIEW LETTERS 74 (21) 4141 - 4144 0031-9007 1995/05 [Refereed][Not invited]
  
• COULOMB DISSOCIATION OF HE-6 AND LI-11 AND ITS EFFECT ON THE ELASTIC-SCATTERING

  Y SAKURAGI, S FUNADA, Y HIRABAYASHI

  NUCLEAR PHYSICS A 588 (1) C65 - C69 0375-9474 1995/05 [Refereed][Not invited]
  
• COULOMB DISSOCIATION OF HE-6 AND LI-11 AND ITS EFFECT ON THE ELASTIC-SCATTERING

  Y SAKURAGI, S FUNADA, Y HIRABAYASHI

  NUCLEAR PHYSICS A 588 (1) C65 - C69 0375-9474 1995/05 [Refereed][Not invited]
  
• Theoretical Study of 16O → α + 12C Breakup Reaction

  Y. Hirabayashi, Y. Sakuragi

  Proc. Int. Symp. Tours Symposium on Nuclear Physics II 118 - 125 1995 [Refereed][Not invited]
  
• Breakupo of 16O on The Way to The Astrophysical Problem in Astrophysical Interes

  H. Utsunomiya, M. Yamagami, Y. Hirabayashi, M. Hirai, H. Sakurai, T. Ichihara, M. Kamimura, S. Kato, S. Kubono, T. Motobayashi, S. Okabe

  Proc. Int. Symp. Tours Symposium on Nuclear Physics II 126 - 131 1995 [Refereed][Not invited]
  
• SUCCESSFUL DESCRIPTION OF ELASTIC-SCATTERING OF HE-3 PARTICLES AT 150-MEV/NUCLEON WITH THE SINGLE FOLDING POTENTIAL MODEL

  T YAMAGATA, H UTSUNOMIYA, S NAKAYAMA, H KOORI, M TANAKA, A TAMII, Y FUJITA, K KATORI, M INOUE, M FUJIWARA, H OGATA, Y HIRABAYASHI

  PHYSICAL REVIEW C 50 (5) 2606 - 2607 0556-2813 1994/11 [Refereed][Not invited]
  
• SINGLE-FOLDING INTERACTION IN SCATTERING OF LI-6 AND LI-7 FROM NUCLEI

  Y HIRABAYASHI, Y SAKURAGI, M TANIFUJI

  PHYSICS LETTERS B 318 (1) 32 - 38 0370-2693 1993/11 [Refereed][Not invited]
   

  Single-folding (SF) interactions in coupled-channel calculations, which include projectile excitations, are investigated for scattering of Li-6 and Li-7 from Sn-120 and Mg-26 nuclei at 44 MeV. The calculations reproduce well measured cross sections and analyzing powers, when the interaction strength is reduced by a large amount. The reduction counterbalances the overestimation of the interaction at the nuclear surface region.
• EVIDENCE FOR STRONG NUCLEAR-BREAKUP CONTRIBUTION TO LI-6-]ALPHA+D BREAKUP BY PB-208 AT FORWARD ANGLES

  Y HIRABAYASHI, Y SAKURAGI

  PHYSICAL REVIEW LETTERS 69 (13) 1892 - 1895 0031-9007 1992/09 [Refereed][Not invited]
   

  The nuclear-breakup and Coulomb-breakup contributions to the sequential breakup of 156-MeV Li-6 by Pb-208 via the 3+ resonance state of Li-6 at 2.186 MeV are investigated by three-body calculations based on the continuum-discretized coupled-channels method. The nuclear-breakup contribution is as important as the Coulomb-breakup one up to forward angles where the Coulomb breakup was believed to be dominant. The effects of multistep processes via various nonresonant continuum states due to the three-body dynamics are also found to be important.
• COUPLED-CHANNELS STUDY OF POLARIZED LI-6 SCATTERING AT 44 MEV

  Y HIRABAYASHI, Y SAKURAGI

  NUCLEAR PHYSICS A 536 (2) 375 - 396 0375-9474 1992/01 [Refereed][Not invited]
   

  Previously published coupled-channels (CC) analyses by Rusek et al. of polarized Li-6 elastic scattering by Mg-26 and Sn-120 at E(lab) = 44 MeV are reanalyzed. Excitations of Li-6 to its three lowest T = 0 excited states are taken into account in the framework of continuum-discretized coupled-channels (CDCC). The analyses are made with the use of the projectile-target interactions based on the cluster-folding (CF) model and those on the double-folding (DF) one. It is shown that the coupling to the Li-6-excited states has large contributions to the vector and tensor analyzing powers of the elastic scattering. A test of the accuracy of the weak-binding-energy approximation (WBEA), which was used in the previous analyses, is made in comparison with the results of the CDCC calculation. It is also pointed out that there exists an ambiguity in the deuteron-target spin-orbit interaction, which affects the conclusion on the competition between the folding spin-orbit interaction and the projectile-excitation effects in the vector analyzing power.
• EFFECTS OF NONRESONANT BREAKUP STATES IN POLARIZED LI-6 SCATTERING

  Y HIRABAYASHI

  PHYSICAL REVIEW C 44 (4) 1581 - 1587 0556-2813 1991/10 [Refereed][Not invited]
   

  Effects of the coupling to Li-6 --> alpha + d nonresonant continuum states on polarized Li-6 scattering at E(lab) congruent-to 20-100 MeV are investigated in the framework of the continuum-discretized coupled-channels (CDCC) method which takes into account the resonant and nonresonant alpha-d breakup states of Li-6. A convergence of the calculated analyzing powers of Li-6 elastic scattering against the size and the discretization of the breakup continuum is examined. The resulting model space of the breakup states consists of the alpha-d S-wave (l = 0), P-wave (l = 1), and D-wave (l = 2) states up to the alpha-d relative momentum of k = 1.2 fm-1. The results of the CDCC calculation show that the effects of the nonresonant breakup states are quite as significant on the analyzing powers as those of the resonant breakup states.
• ANOMALOUS RENORMALIZATION OF CLUSTER-FOLDING INTERACTIONS FOR LI-6-NUCLEUS SCATTERING AT LOW ENERGIES

  Y HIRABAYASHI, Y SAKURAGI

  PHYSICS LETTERS B 258 (1-2) 11 - 16 0370-2693 1991/04 [Refereed][Not invited]
   

  The validity of cluster-folding (CF) interactions for elastic scattering of Li-6 by various nuclei is investigated in the alpha + d + target three-body model. The Li-6 --> alpha + d breakup process is taken into account in the framework of the continuum-discretized coupled-channels (CDCC). It is shown that, at low energies below E(lab)/A(p) congruent-to 10 MeV, the real part of the CF potentials has to be reduced by about (40-50)%, even when the resonant and non-resonant breakup channels are explicitly included in the CDCC calculations, while no renormalization is necessary for fits to scattering at higher energies.
• Is Coulomb Dissociation Method Applicable to Astrophysics ?

  Y. Sakuragi, Y. Hirabayashi

  Proc. Int. Symp. Origin and Evolution of the Elements 220  1991 [Refereed][Not invited]
  
• LI-11-]LI-9+2N BREAKUP EFFECT ON LI-11-NUCLEUS ELASTIC-SCATTERING

  Y HIRABAYASHI, S FUNADA, Y SAKURAGI

  STRUCTURE AND REACTIONS OF UNSTABLE NUCLEI 227 - 232 1991 [Refereed][Not invited]
  
• COUPLED-CHANNELS ANALYSIS OF POLARIZED LI-6 SCATTERING AT 44 MEV

  Y HIRABAYASHI, Y SAKURAGI

  INSTITUTE OF PHYSICS CONFERENCE SERIES 110 (110) 323 - 330 0951-3248 1991 [Refereed][Not invited]
   

  Recently published coupled-channels calculations of 44 MeV polarised Li-6 scattering by Mg-26 and Sn-120 are examined. It is shown that a consistent treatment of the projectile excitation based on the cluster model leads to a quite different conclusion from that of the previous analysis on the competition between the static and dynamical effects on the spin-orbit and tensor interactions. An importance of the careful examination of the d-target spin-orbit potential is also pointed out. A prediction on the scattering of polarised Li-6 in the energy range of Daresbury Tandem accelerator is presented.
• COUPLED-CHANNELS ANALYSIS OF POLARIZED LI-6 SCATTERING AT 44 MEV

  Y HIRABAYASHI, Y SAKURAGI

  HEAVY ION COLLISIONS AT ENERGIES NEAR THE COULOMB BARRIER 1990 110 323 - 330 1991 [Refereed][Not invited]
  
• Projectile breakup effect in elastic and inelastic scattering of 9Be

  Y. Hirabayashi

  Proceedings of the RIKEN Synposium on LIGHT AND LIGHT-HEAVY INO REACTIONS 174 - 183 1989/12 [Refereed][Not invited]
  
• PROJECTILE BREAKUP EFFECT IN ELASTIC-SCATTERING OF BE-9

  Y HIRABAYASHI, S OKABE, Y SAKURAGI

  PHYSICS LETTERS B 221 (3-4) 227 - 232 0370-2693 1989/05 [Refereed][Not invited]
  
• Roles of Breakup Processes in Light Heavy-Ion Scattering

  Y. Sakuragi, Y. Hirabayashi

  Proc. Fifth Int. Conf. Clustering Aspects in Nucl. and Subnucl. Systems 58 (suppl.) 560 - 566 1988 [Refereed][Not invited]
  

MISC

• 27aTR-3 ^3He(K^-, π^-)Λpp reactions and continuum states

  Harada T., Hirabayashi Y.  Meeting abstracts of the Physical Society of Japan  69-  (1)  71  -71  2014/03/05
• 23aSB-4 Observation of an Airy minimum in prerainbow scattering of ^3He from ^12C and α-particle condensation of the Hoyle state

  Hamada Sh., Hirabayashi Y., Burtebayev N., Ohkubo S.  Meeting abstracts of the Physical Society of Japan  68-  (2)  46  -46  2013/08/26
• 23aSB-5 Inelastic α+^<16>O scattering and α-cluster structure with core excitation in ^<20>Ne

  Hirabayashi Y., Ohkubo S.  Meeting abstracts of the Physical Society of Japan  68-  (2)  46  -46  2013/08/26
• 27aHB-4 Continuum Λpp spectra in hypernuclear production

  Harada T., Hirabayashi Y.  Meeting abstracts of the Physical Society of Japan  68-  (1)  53  -53  2013/03/26
• 12pSA-4 Hypernuclear production spectra on a ^3He target

  Harada T., Hirabayashia Y.  Meeting abstracts of the Physical Society of Japan  67-  (2)  38  -38  2012/08/24
• 18aSG-8 Hypernuclear spectra from K^- capture at rest in ^3He

  Harada T., Hirabayashi Y.  Meeting abstracts of the Physical Society of Japan  66-  (2)  84  -84  2011/08/24
• Complex-scaled cdcc method for nuclear breakup reactions

  M. Takashina, M. Takashina, T. Myo, T. Myo, Y. Hirabayashi, Y. Kikuchi, K. Kato  Hadron and Nuclear Physics 2009, HNP 2009  361  -365  2010/12/01  [Not refereed][Not invited]
   

  In this talk, we propose applying the complex-scaling method to CDCC, where the internal coordinate and momentum of projectile nucleus are complex- scaled. We show that the continuous S matrix element of breakup reaction is obtained without smoothing function.
• 12pSE-1 Production of doubly strange hypernuclei in the (K^-,K^+) reaction

  Harada T., Hirabayashi Y., Umeya A.  Meeting abstracts of the Physical Society of Japan  65-  (2)  39  -39  2010/08/18
• α-particle condensation states in 16O

  S. Ohkubo, Y. Hirabayashi  2nd International Workshop on State of the Art in Nuclear Cluster Physics SOTANCP2 (Belgium): Book of Abstracts  66  2010/05  [Not refereed][Not invited]
  
• 20aBD-10 Double-Charge Exchange Reactions and Hypernuclei

  Harada T., Hirabayashi Y., Umeya A.  Meeting abstracts of the Physical Society of Japan  65-  (1)  33  -33  2010/03/01
• 二体(⁴He+d),三体(⁴He+p+n)クラスター模型を用いた⁶Liの構造とE2遷移強度

  和野惇, 菊地右馬, 平林義治, 明孝之, 加藤幾芳  原子核研究  54-  (Supplement 1)  110  -113  2010/02  [Not refereed][Not invited]
  
• 27aSJ-3 Hypernuclear Productions by Double-Charge Exchange Reactions

  Harada T., Umeya A., Hirabayashi Y.  Meeting abstracts of the Physical Society of Japan  64-  (1)  63  -63  2009/03/03
• 28aXF-9 Complex-scaled CDCC (continuum-discretized coupled-channel) method

  Takashina M., Myo T., Kikuchi Y., Hirabayashi Y., Kato K.  Meeting abstracts of the Physical Society of Japan  64-  (1)  46  -46  2009/03/03
• 28aXF-8 α+d elastic scattering using complex-scaled solutions of Lippmann-Schwinger equation

  Kikuchi Y., Kato K., Hirabayashi Y., Myo T., Takashina M.  Meeting abstracts of the Physical Society of Japan  64-  (1)  46  -46  2009/03/03
• 28aSG-10 α cluster structure of ^<12>C with the ^<12>C(p,p') reaction

  Okamoto A, Yamagata T, Akimune H, Utsunomiya H, Hara K. Y, Kinoshita M, Ikemizu H, Nakayama S, Fushimi K, Hayami R, Matsumoto E, Fujiwara M, Hara K, Hashimoto N, Kawase K, Nakanishi K, Yosoi M, Greenfield M. B, Tanaka M, Hirabayashi Y  Meeting abstracts of the Physical Society of Japan  64-  (1)  70  -70  2009/03/03  [Not refereed][Not invited]
  
• 二体(⁴He+d),三体(⁴He+p+n)クラスター模型を用いた⁶Liの構造とd(α,γ)⁶Li反応

  和野惇, 菊地右馬, 平林義治, 明孝之, 加藤幾芳  原子核研究  53-  (Supplement 1)  96  -99  2009/03  [Not refereed][Not invited]
  
• 23aSA-4 Structure and ^4He+d scattering for ^6Li with ^4He+p+n model

  Wano Atsushi, Kikuchi Yuma, Hirabayashi Yoshiharu, Myo Takayuki, Kato Kiyoshi  Meeting abstracts of the Physical Society of Japan  63-  (2)  44  -44  2008/08/25
• オープンコースウェアによる映像資料の作成と公開

  合川 正幸, 津田 麻里江, 渡邉 浩平, 田邉 鉄, 長野 督, 野坂 政司, 平林 義治, 布施 泉, 山本 裕一, 岡部 成玄  2008PCカンファレンス論文集  328  -329  2008/08  [Not refereed][Not invited]
  
• 23pZG-7 Neutron-rich Hypernuclei and Production Reaction Processes

  Harada T., Umeya A., Hirabayashi Y.  Meeting abstracts of the Physical Society of Japan  63-  (1)  37  -37  2008/02/29
• オープンコースウェアでの講義資料公開と著作権

  合川 正幸, 津田 麻里江, 田邉 鉄, 野坂 政司, 平林 義治, 布施 泉, 山本 裕一, 渡邉 浩平, 岡部 成玄  2007PCカンファレンス論文集  327  -330  2007/08  [Not refereed][Not invited]
  
• オープンコースウェアでの講義資料公開と著作権処理

  合川 正幸, 津田 麻里江, 田邉 鉄, 野坂 政司, 平林 義治, 布施 泉, 山本 裕一, 渡邉 浩平, 岡部 成玄  平成18年度情報教育研究集会講演論文集  711  -713  2006/11  [Not refereed][Not invited]
  
• 30pWB-3 Is the Σ-nucleus potential for Σ^- atoms consistent with the (π^-,K^+) data?

  Harada Toru, Hirabayashi Yoshiharu  Meeting abstracts of the Physical Society of Japan  61-  (1)  78  -78  2006/03/04
• Bose-Einstein condensation of alpha particles and Airy structure in nuclear rainbow scattering

  S Ohkubo, Y Hirabayashi  PHYSICAL REVIEW C  70-  (4)  041602(R)  2004/10  [Not refereed][Not invited]
   

  It is shown that the dilute density distribution of alpha particles in nuclei can be observed in the Airy structure in nuclear rainbow scattering. We have analyzed alpha+C-12 rainbow scattering to the 0(2)(+) (7.65 MeV) state of C-12 in a coupled-channel method with the precise wave functions for C-12. It is found that the enhanced Airy oscillations in the experimental angular distributions for the 0(2)(+) state is caused by the dilute density distribution of this state in agreement for the idea of Bose-Einstein condensation of the three alpha particles.
• 27aZH-4 (π,K^+) Reactions and Impulse Apporximation

  Harada Toru, Hirabayashi Yoshiharu  Meeting abstracts of the Physical Society of Japan  59-  (1)  27  -27  2004/03/03
• Optimal Fermi-averaging for the pi+ + n -> K+ + Lambda t-matrix in Lambda-hypernuclear production from (pi+,K+) reactions

  NUCLEAR PHYSICS A  744, 323-  2004  [Not refereed][Not invited]
  
• Multicluster configuration in highly excited states of Mg-24

  M Ito, Y Hirabayashi, Y Sakuragi  PHYSICAL REVIEW C  66-  (3)  034307  2002/09  [Not refereed][Not invited]
   

  The nuclear structure of Mg-24 with C-12+3alpha and 3alpha+3alpha configurations, existing at an extremely highly-excited energy domain is studied by the microscopic coupled-channels (MCC) calculation based on the double-folding interactions using 3alpha-RGM wave functions of C-12 and a realistic nucleon-nucleon interaction called DDM3Y. The dinuclear C-12+C-12 configuration of Mg-24, corresponding to the so-called "higher-energy molecular resonances," is also investigated by the same MCC framework. The MCC calculation predicts the existence of three kinds of the molecular bands having 3alpha+3alpha, C-12+3alpha, and C-12+C-12 structures around the excitation energy of about 40 MeV with respect to the ground state of Mg-24. The channel coupling among the 3alpha states in each C-12 plays very important roles for the formation of the C-12+3alpha and 3alpha+3alpha molecular bands. It is found that the populations of the C-12(g.s.)+C-12(g.s.), C-12(g.s.)+C-12(0(2)(+)), and C-12(0(2)(+))+C-12(0(2)(+)) channels are very small in the individual molecular bands with C-12+C-12, C-12+3alpha, and 3alpha+3alpha configurations, respectively. The reaction mechanism for the inelastic scattering leading to the C-12(g.s.)+C-12(0(2)(+)) and C-12(0(2)(+))+C-12(0(2)(+)) excitation channels is also investigated in relation to the obtained three kinds of the molecular bands. The result suggests that the inelastic scattering to the C-12(0(2)(+))+C-12(0(2)(+)) [C-12(g.s.)+C-12(0(2)(+))] channel can be interpreted in terms of weak transitions from the C-12(g.s.)+C-12(g.s.) component of the C-12+C-12 molecular bands to the C-12(0(2)(+))+C-12(0(2)(+)) [C-12(g.s.)+C-12(0(2)(+))] component of the multicluster 3alpha+3alpha (C-12+3alpha) molecular bands. All the results are discussed in connection with the band crossing model which was proposed in describing the higher-energy molecular resonance with dinuclear configuration as well as the resonances observed in the C-12(0(2)(+))+C-12(0(2)(+)) and C-12(g.s.)+C-12(0(2)(+)) exit channels.
• Alpha Scattering from Nonclosed Shell Nucleus $^{12}$C and Alpha-Nucleus Interaction

  Physics of Atomic Nuclei  65, 683-  2002  [Not refereed][Not invited]
  
• New distorted-wave impulse approximation calculation for inelastic scattering of deuterons at intermediate energies with the sudden approximation approach

  Y Hirabayashi, T Suzuki, M Tanifuji  PHYSICAL REVIEW C  64-  (5)  054605  2001/11  [Not refereed][Not invited]
   

  We perform a distorted-wave impulse approximation calculation of inelastic scattering of deuterons by nuclei using effective interactions in the framework of the sudden approximation at E-d=400 MeV, Cross sections and spin observables are expressed in terms of amplitudes for the corresponding nucleon-nucleus scattering. The calculation is examined for the excitation of C-12 to the 2(+) (2.44 MeV), 3(-) (9.64 MeV), and 1(+) (12.71 MeV) states and is found to give a reasonable description for most of the observables. Some discrepancies are found for the transition leading to the 1(+) state, Suggesting the limitation of the applicability of the effective interaction. Contributions of the deuteron D state are studied. Relations between the deuteron-nucleus and proton-nucleus scattering observables are found and are studied against existing data.
• Properties of microscopic nucleus-nucleus interaction for molecular resonance formation in C-12+C-12 and 3 alpha+3 alpha systems

  M Ito, Y Sakuragi, Y Hirabayashi  PHYSICAL REVIEW C  63-  (6)  064304  2001/06  [Not refereed][Not invited]
   

  Properties of microscopic interaction potentials between two C-12 nuclei are discussed;in connection with the formation of C-12 + C-12 and 3 alpha + 3 alpha molecular resonances. The nucleus-nucleus in are calculated by the double-folding procedure based on a realistic nucleon-nucleon interaction (DDM3Y) and microscopic C-12 transition densities calculated from 3 alpha -RGM wave functions. The interaction potential can written as the sum of the monopole part obtained from the monopole density and the multiple generated from the quadrupole component of the density. We discuss the role of the monopole and multipole parts of the potential separately. It is shown that the multipole part is very strong in the channels with 3 alpha + 3 alpha structure and the energy positions of the 3 alpha + 3 alpha molecular bands generated by the monopole potential are largely modified. The effect is moderate but non-negligible on the molecular bands with the C-12 + C-12 dinuclearlike structure and largely modifies the band crossing diagram between the elastic and aligned-inelastic molecular bands. The channel coupling effect among the C-12 + C-12 channels, namely, the elastic channel and the single- and mutual-2(1)(+) excitation channels is also investigated. Due to the strong coupling between the ground and 2(1)(+) states of C-12, the resonance wave functions obtained by the coupled-channel calculation have an additional radial node compared with those of the single-channel resonances. All the results are discussed in connection with the band crossing model which was believed to be successful in describing the C-12 + C-12 molecular resonances.
• Channel coupling effects in resonant breakup of 42 MeV Li-7 with Ni-58 target

  D Gupta, C Samanta, A Chatterjee, K Rusek, Y Hirabayashi  JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS  26-  (6)  L81  -L86  2000/06  [Not refereed][Not invited]
   

  The angular distribution of the 42 MeV Li-7 sequential breakup (via 7/2(-), 4.63MeV state) with Ni-58 target, measured beyond the grazing angle, is presented. Analyses of both elastic scattering and sequential breakup are carried out in a continuum-discretized coupled channel framework. In sequential breakup, contributions from multi-step processes are found to be significant at this low incident energy.
• Relation between(p,p')and(d,d')on¹²C in the sudden approximation

  Proc. RCNP-TMU Symp. Spin in Nuclear and Hadronic Reactions(World Scientific)  56  2000  [Not refereed][Not invited]
  
• Microscopic Coupled-Channel Study of¹²C+¹²C Resonance Reactions

  Few-Body Systems Suppl.  12-  137  2000  [Not refereed][Not invited]
  
• Microscopic coupled-channel study of heavy-ion resonances in multi-cluster exit channels

  Y Sakuragi, M Ito, M Katsuma, M Takashina, Y Kudo, Y Hirabayashi, S Okabe, Y Abe  PROCEEDINGS OF THE 7TH INTERNATIONAL CONFERENCE ON CLUSTERING ASPECTS OF NUCLEAR STRUCTURE AND DYNAMICS  138  -142  2000  [Not refereed][Not invited]
   

  Heavy-ion resonances recently discovered in nuclear collisions of C-12+C-12 and O-16+O-16 systems leading to multi-cluster exit channels, C-12+C-12 --> 3 alpha+C-12, 3 alpha +3 alpha, 2 alpha+O-16 and O-16+O-16 --> (alpha+C-12)+O-16, (alpha+C-12)+(alpha+C-12), are studied theoretically by the coupled-channel (CC) and coupled-channel Born approximation (CCBA) calculations using microscopic cluster-model wave functions of the colliding nuclei, C-12 and O-16, and nucleus-nucleus interactions based on the realistic G-matrix interaction. These resonance states correspond to highly excited states of the compound systems, Mg-24 and S-32 nuclei, at excitation energies more than 40 similar to 55 MeV. The the microscopic CC and CCBA calculations well reproduce the characteristic features of these new resonance states.
• Dynamic polarization potential of C-12+C-12 system at molecular-resonance energies

  M Ito, Y Sakuragi, Y Hirabayashi  EUROPEAN PHYSICAL JOURNAL A  5-  (4)  373  -383  1999/08  [Not refereed][Not invited]
   

  The nuclear reaction dynamics leading to the formation of recently discovered resonance in the mutual-0(2)(+) channel of the C-12+C-12 inelastic scattering around E-c.m. similar or equal to 32 MeV is studied in terms of the dynamic polarization potential(DPP) induced by the channel coupling among various excited states in C-12. The microscopic 3 alpha cluster-model wave functions are used to generate the C-12-C-12 diagonal and coupling potential in the double-folding model. It is found that DPP for the 0(2)(+) + 0(2)(+) channel is an unusually strong attractive potential which even exceeds the zeroth-order folding-model potential of this channel around the nuclear surface region and that the strong coupling between the 0(2)(+) and 2(2)(+) states is predominantly responsible for the unusual DPP in this channel. The effective potential, the sum of the original folding-model potential and the attractive DPP, is found to generates resonance states in the same energy region as that of the resonance states generated by the original folding-model potential but the former states are found to be higher-nodal states having four additional radial nodes. Similar but more moderate property of DPP is also found in the entrance (elastic) channel. These results suggest that the reaction dynamics of generating the resonance in the C-12(0(2)(+)) + C-12(0(2)(+)) channel may rather differ from that of the simple crossing of the zeroth-order molecular band generated by the potentials in the entrance and exit channels suggested by the standard band-crossing model.
• Multi-Cluster Structure of Highly Excited States in ^<24>Mg I

  ITO M., SAKURAGI Y., HIRABAYASHI Y., ABE Y.  Meeting abstracts of the Physical Society of Japan  53-  (1)  35  -35  1998/03/10
• 3 alpha+3 alpha structure of highly excited states in Mg-24

  M Ito, Y Sakuragi, Y Hirabayashi, Y Abe  PROCEEDINGS OF THE XVII RCNP INTERNATIONAL SYMPOSIUM ON INNOVATIVE COMPUTATIONAL METHODS IN NUCLEAR MANY-BODY PROBLEMS  229  -231  1998  [Not refereed][Not invited]
   

  We have analysed the highly-excited states of Mg-24 around 30 MeV above the 6 alpha threshold in a microscopic coupled-channels framework and we have identified several rotational bands having a 3 alpha+3 alpha structure in this energy region, which cross with the other kind of rotational bands having C-12+C-12 structure. The relation of these band structures and the resonance recently observed in the C-12(O-2(+))+C-12(O-2(+)) reaction is discussed.
• Heavy-ion resonance and multi-cluster states in highly excited nuclei

  Y Sakuragi, M Ito, M Katsuma, M Takashina, Y Hirabayashi, S Okabe, Y Abe  PROCEEDINGS OF THE XVII RCNP INTERNATIONAL SYMPOSIUM ON INNOVATIVE COMPUTATIONAL METHODS IN NUCLEAR MANY-BODY PROBLEMS  196  -204  1998  [Not refereed][Not invited]
   

  Heavy-ion resonances recently observed in the collisions of C-12+C-12 and O-16+O-16 systems leading to the multi-cluster exit channels are studied theoretically. The excitation of C-12 and O-16 to the states having the 3 alpha and alpha+C-12 cluster configurations are explicitly taken into account by the coupled-channels (CC) calculation using microscopic form factors based on the microscopic cluster-model wave functions. The calculation reproduces the essential features of the resonances observed in the multi-cluster exit channels surprisingly well. A prominent resonance structure is also predicted in the Be-8+O-16 system by the CC calculation with the Be-8 excitations treated explicitly, which suggests a possible explanation of the resonances observed in the C-12+C-12 --> B-8+O-16 alpha-transfer reactions.
• α-cluster structure of ⁴⁴Ti in core-excited α+⁴⁰Ca model

  Physical Review C  57-  (5)  2760  -2762  1998  [Not refereed][Not invited]
  
• Breakup effect on the Li-6 elastic scattering from Si-28 at E/A=35 and 53 MeV

  Y Sakuragi, M Ito, Y Hirabayashi, C Samanta  PROGRESS OF THEORETICAL PHYSICS  98-  (2)  521  -525  1997/08  [Not refereed][Not invited]
   

  The effect of projectile breakup on the Li-6 elastic scattering from Si-28 at E/A = 35 and 53 MeV is investigated with the continuum-discretized coupled-channels method using the double-folding model interactions based on the density-dependent M3Y (DDM3Y) interaction. It is shown that the breakup effect is still important and of a repulsive nature at these incident energies.
• 28a-YM-3 Sudden Aproximation for Inelastic Scattering of Polarized Deuteron

  Suzuki Toru, Hirabayashi Yoshiharu, Tanifuji Makoto  Meeting abstracts of the Physical Society of Japan  52-  (1)  37  -37  1997/03/17
• Breakup of 30 MeV/u-O-16 in nuclear and Coulomb fields of Sn-120 and Pb-208 nuclei

  D OKelly, T Botting, B Hurst, RP Schmitt, YW Lui, Y Hirabayashi, S Okabe, Y Sakuragi, H Utsunomiya, T Yamagata, M Ohta  PHYSICS LETTERS B  393-  (3-4)  301  -306  1997/02  [Not refereed][Not invited]
   

  Coincidence measurements of alpha-C-12 pairs collinearly emitted in the breakup of 30 MeV/u- O-16 incident on Pb-208 and Sn-120 were performed with a two detector system set up along the focal plane of a magnetic spectrograph. Double differential cross sections for sequential breakup via the 2(2)(+) and 2(3)(+) states in O-16 were analyzed within the framework of coupled-channels (CC) calculations which incorporated microscopic alpha-C-12 cluster model wave functions for bound and unbound states of O-16, The experimental data are satisfactorily reproduced by the CC calculations to within a factor of two. The results are discussed in terms of the interference between nuclear- and Coulomb-breakup amplitudes.
• 3-ALPHA+3-ALPHA AND 3-ALPHA+C-12 CONFIGURATIONS IN MG-24 (VOL 74, PG 4141, 1995)

  Y HIRABAYASHI, Y SAKURAGI, Y ABE  PHYSICAL REVIEW LETTERS  75-  (20)  3779  -3779  1995/11  [Not refereed][Not invited]
  
• Coulomb dissociation of 6He and 11Li and its effect on the elastic scattering

  Y. Sakuragi, S. Funada, Y. Hirabayashi  Nuclear Physics, Section A  588-  (1)  c65  -c69  1995/05/29  [Not refereed][Not invited]
  
• 3-ALPHA+3-ALPHA AND 3-ALPHA+C-12 CONFIGURATIONS IN MG-24

  Y HIRABAYASHI, Y SAKURAGI, Y ABE  PHYSICAL REVIEW LETTERS  74-  (21)  4141  -4144  1995/05  [Not refereed][Not invited]
  
• Coulomb Dissociation of Halo Nuclei and its Effect on Elastic Scattering

  Third IN2T3-RIKEN Symposium on Heavy Ion Collisions (World Sientific)  39  1995  [Not refereed][Not invited]
  
• Breakup of ¹⁶O on The Way to The Astrophysical Problem

  ours symposium on Nuclear Physics 〓(World Scientiffic)  126  1995  [Not refereed][Not invited]
  
• Theoretical Study of ¹⁶→2+¹²C Breakup Reaction in Astophysical interest

  Tours symposium on Nuclear Physics 〓(World Scientiffic)  118  1995  [Not refereed][Not invited]
  
• 30a-F-5 Effect of Soft-Mode Excitation on the Scattering of^6He and ^<11>Li

  FUNADA S, SAKURAGI Y, HIRABAYASHI Y  Abstracts of the meeting of the Physical Society of Japan. Sectional meeting  1994-  (1)  67  -67  1994/09/12
• 28a-Y-5 Elastic scattering of ^3He particles at 450 Mev

  山県 民穂, 宇都宮 弘章, 田中 正義, 中山 信太郎, 桑折 範彦, 民井 淳, 藤田 佳孝, 鹿取 謙二, 井上 信, 藤原 守, 小方 寛, 平林 義治  Abstracts of the meeting of the Physical Society of Japan. Annual meeting  49-  (1)  104  -104  1994/03/16
• Successful description of elastic scattering of ³He particles at 150MeV/nucleon with the single folding potential model(共著)

  PHYSICAL REVIEW C  50-  (5)  2606  -2607  1994  [Not refereed][Not invited]
  
• SINGLE-FOLDING INTERACTION IN SCATTERING OF LI-6 AND LI-7 FROM NUCLEI

  Y HIRABAYASHI, Y SAKURAGI, M TANIFUJI  PHYSICS LETTERS B  318-  (1)  32  -38  1993/11  [Not refereed][Not invited]
   

  Single-folding (SF) interactions in coupled-channel calculations, which include projectile excitations, are investigated for scattering of Li-6 and Li-7 from Sn-120 and Mg-26 nuclei at 44 MeV. The calculations reproduce well measured cross sections and analyzing powers, when the interaction strength is reduced by a large amount. The reduction counterbalances the overestimation of the interaction at the nuclear surface region.
• ^6Li→α+d and ^7Li→α+t Breakup Reactions in a Strong Coulomb Field(Microscopic Cluster Models of Light Nuclei and Related Topics)

  Hirabayashi Yoshiharu  Soryushiron Kenkyu  87-  (2)  B68  -B83  1993/05/20  

  The nuclear-breakup and Coulomb-breakup contributions to ^6Li → α + d and ^7Li → α + t breakup reactions which are used to access to the radiative capture reactions important in nuclear astrophysics are investigated by three-body calculations with the use of the realistic cluster-model wave functions for the bound and unbound states of ^6Li and ^7Li. For incident energies well above the Coulomb barrier, the nuclear-breakup contribution is as important as the Coulomb-breakup one up to forward angles where the Coulomb breakup was believed to be dominant. The effects of multi-step processes via various nonresonant continuum states due to the three-body dynamics are also found to be important. On the other hand, at sub-barrier energies the Coulomb-breakup contribution dominates over the nuclear-breakup one and the effect of multi-step process may be factored out.
• 3p-D-5 Nuclear-Breakup Contribution to ^7Li→α+t Reaction in a Strong Coulomb Field

  Hirabayashi Y, Sakuragi Y  秋の分科会講演予稿集  1992-  (1)  76  -76  1992/09/14
• COUPLED-CHANNELS STUDY OF POLARIZED ⁶Li SCATTERING AT 44 MeV(共著)

  NUCLEAR PHYSICS A  536-  (2)  375  -396  1992  [Not refereed][Not invited]
  
• Evidence for Strong Nuclear-Breakup Contribution to ⁶Li→α+d Breakup by ²⁰⁸Pb at Forward Angles(共著)

  PHYSICAL REVIEW LETTERS  69-  (13)  1892  -1895  1992  [Not refereed][Not invited]
  
• Is Coulomb Dissosiation Method Applicable to Astrophysics?

  Origin and Evolution of the Elements (World Sientific)  220  1991  [Not refereed][Not invited]
  
• LI-11-]LI-9+2N BREAKUP EFFECT ON LI-11-NUCLEUS ELASTIC-SCATTERING

  Y HIRABAYASHI, S FUNADA, Y SAKURAGI  STRUCTURE AND REACTIONS OF UNSTABLE NUCLEI  227  -232  1991  [Not refereed][Not invited]
  
• COUPLED-CHANNELS ANALYSIS OF POLARIZED LI-6 SCATTERING AT 44 MEV

  Y HIRABAYASHI, Y SAKURAGI  INSTITUTE OF PHYSICS CONFERENCE SERIES  (110)  323  -330  1991  [Not refereed][Not invited]
   

  Recently published coupled-channels calculations of 44 MeV polarised Li-6 scattering by Mg-26 and Sn-120 are examined. It is shown that a consistent treatment of the projectile excitation based on the cluster model leads to a quite different conclusion from that of the previous analysis on the competition between the static and dynamical effects on the spin-orbit and tensor interactions. An importance of the careful examination of the d-target spin-orbit potential is also pointed out. A prediction on the scattering of polarised Li-6 in the energy range of Daresbury Tandem accelerator is presented.
• Anomolous renormalization of cluster-folding interactions for ⁶Li-nucleus scattering at low energies(共著)

  PHYSICS LETTERS B  258-  (1)  2,11  1991  [Not refereed][Not invited]
  
• Effects of nonresonant breakup states in polarized ⁶Li scattering

  PHYSICAL REVIEW C  44-  (4)  1581  -1587  1991  [Not refereed][Not invited]
  
• PROJECTILE BREAKUP EFFECT IN ELASTIC-SCATTERING OF BE-9

  Y HIRABAYASHI, S OKABE, Y SAKURAGI  PHYSICS LETTERS B  221-  (3-4)  227  -232  1989/05  [Not refereed][Not invited]
  
• Roles of Breakup Processes in Light Heavy-Ion Scattering

  Supplement of the Journal of the Physical Society of Japan  58-  560  1989  [Not refereed][Not invited]
  

Association Memberships

• e-Learning教育学会   日本物理学会   

Research Projects

• 漫画を媒介した物語創作と作中人物評価を起点とする情報倫理の発達段階深化手法の開発

  日本学術振興会：科学研究費助成事業

  Date (from‐to) : 2022/04 -2025/03 

  Author : 布施 泉, 山本 裕一, 平林 義治, 西野 和典

   

  本研究では，学習者が生涯学び続ける前提に立ち，SNS等の個人の情報発信が重要度を増す社会において，役割取得能力を重視した情報倫理の発達段階を規定すること，また学習者がその段階を深化させるために必要な学習要件を明らかにすること，さらには，その深化に寄与する教材や学習フレームワークを開発し，学習者の情報倫理の発達段階の深化を実際に評価・確認し，その有用性を明らかにすることを目的としている。 本研究では，情報倫理の発達段階を評価する際，複数の登場人物の視点に立つことを求めるとともに，それが容易に発想できるジレンマ問題を，ある漫画シーンを起点にした物語創作の連鎖により開発することを特徴とする。 実際の授業実践においては，学習者の発達段階は自己評価・相互評価により評価させ，学習者集団全体の情報倫理の発達段階を深化させることを目指している。また，授業実践を踏まえ，自学可能な生涯学習へのシステム構築についても検討を進めることまでを想定する。 このような状況の中，2022年度は，本研究の基本的な事項となる漫画のシーン開発と，システム構築について取り組んだ。 漫画のシーン開発として，近年話題となっている描画に関するオープンなAIエンジンであるStableDiffusionを用い，各種の種となりうる漫画開発を実践し，利用可能なものを抽出した。さらに，学習者の発達段階を調査するためのシステムとして，Moodleのプラグインを新たに開発した。学習者への問いに対する判断状況の分岐を可視化して確認できるものである。なお，本可視化システムは，現状では教授者側としての確認機能であるが，生涯教育を目指し，可視化状況を学習者側に落とし込むことも今後は検討する。
• 漫画を媒介した物語創作と作中人物評価を起点とする情報倫理の発達段階深化手法の開発

  日本学術振興会：科学研究費助成事業

  Date (from‐to) : 2022/04 -2025/03 

  Author : 布施 泉, 山本 裕一, 平林 義治, 西野 和典
• Production and Decay spectra of doubly strange hypernuclei studied in multi-channels coupling calculations

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research

  Date (from‐to) : 2020/04 -2024/03 

  Author : 原田 融, 平林 義治

   

  本研究は, 多重チャネルに拡張された「多重チャネルを結合したグリーン関数法」を用いて, (K-,K+)反応によるダブルストレンジネス核などの生成・崩壊スペクトルを理論的に明らかにすることを目的にしている。信頼性の高い理論計算を実行するためには, 理論的な取り扱いの検討や改善が不可欠である。２年目の2021年度の研究成果は以下の通りである： （１）原子核を標的にした(K-, K+)反応などの生成スペクトルの反応断面積を理論的に評価するためには, 生成されたハイパー核の構造をともに核反応による生成機構の理解が必要である。その記述法のひとつに我々が開発してきた「最適化フェルミ平均」の方法がある。3,4Heを標的核とする(K-,pi0)反応にこれを適用し, 3,4H_Λの基底状態と励起状態の生成断面積を理論的に求めた。その結果，KEKで行われた3,4H_Λの寿命測定実験によって得られた実験値に一致することが分かった。その成果は，学術雑誌から論文として出版された。 （２）一方で「最適化フェルミ平均」の方法を(K-,pi-)反応のΛハイパー核生成に適用した場合，移行運動量が小さいために計算できないという理論的な適用限界の問題があった。そこで歪曲波による核内の局所運動量を考慮することで 「最適化フェルミ平均」の枠組みを拡張することが可能になり，この問題を解決できることを示した。この研究成果は論文としてまとめ，学術雑誌に投稿した。 （３）大強度陽子加速器施設のE05実験で得られた12Cを標的にした(K-, K+)反応によるΞハイパー核の生成断面積の理論解析を行うために，K-とK+の歪曲波をクライン-ゴルドン方程式を解いて求め, 歪曲波インパルス近似計算の改善を進めた。
• Production and decay spectra of the neutron-rich hypernuclei and effects of channels coupling

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research

  Date (from‐to) : 2016/04 -2019/03 

  Author : HARADA Toru, UMEYA Atsushi, KOIKE Takahisa

   

  We study theoretically production and decay spectra of hypernuclei obtained at J-PARC facilities within a distorted-wave impulse approximation in order to see the effects and role of channel coupling between hypernucler states. The results are as follows: (1) A calculated spectra for a neutron-rich 6H_Lambda hypernucleus via the (pi-, K+) reaction on a 6Li target suggests that the Sigma-mixing probability amounts to about 0.3% via Sigma doorways in comparison with the experimental data. (2) A theoretical analysis shows that the Sigma-5He potential has a repulsive +30 MeV-strength in the real part. (3) Theoretical calculations of the 3He (pi, K) reaction including three-body break-up channels predict that the production cross section of the 3H_Lambda 1/2+ ground state is about 3 μb /sr.
• Production and decay spectra of hypernuclei, and hyperons in nuclear matter

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research

  Date (from‐to) : 2013/04 -2016/03 

  Author : HARADA Toru, HIRABAYASHI Yoshiharu

   

  We theoretically study production and decay spectra of hypernuclear states at J-PARC experiments within a distorted-wave impulse approximation in order to see properties of hyperons in nuclear matter. The results are as follows: (1) We confirm possible existence of a Sigma NN quasi-bound state as the 1/2+ isotriplet state whose signal is clearly observed in the 3He(K-, pi-) spectrum, whereas a peak of the quasi-bound state is rather reduced in the 3He(K-, pi+) spectrum owing to the interference effects. (2) Applying the multichannel Green's function constructed by the CDCC method, we show that the calculated spectrum has the ability to fully describe Lambda-p-p breakup continuum states in 3He(K-, pi-) reactions. (3) We predict that a pole of the S-matrix for a p-wave Sigma resonant state in 4-Sigma-He is located in the complex E plane and that the shape of the conversion spectra in 4He(K-, pi-) reactions provide valuable information on Sigma N and Sigma N-Lambda N interactions.
• Production and decay spectra of hypernuclei by double-charge exchange reactions, and hyperon mixing

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research

  Date (from‐to) : 2010 -2012 

  Author : HARADA Toru, HIRABAYASHI Yoshiharu, UMEYA Atsushi, KOIKE Takahisa

   

  We have theoretically demonstrated production and decay of spectra of hypernuclei by double-charge exchange reactions, e.g. (Ｋ〓，Ｋ〓), (π〓，Ｋ〓), using the distorted-wave impulse approximation. A one-step reaction mechanism, in which adoorway state is populated owing to a hyperon mixing, has been investigated. The result shows that these spectra provide valuable information on properties of the 〓Ν－ΛΛ andΣΝ－ΛΝcoupling interactions in a comparison with the forthcoming J-PARC facilities, and it is strongly related to understanding of the inner structure of neutron stars.
• 徴視的チャネル結合法による天体核物理周辺の核反応の研究

  日本学術振興会：科学研究費助成事業

  Date (from‐to) : 1997 -1998 

  Author : 平林 義治

   

  星の元素合成に重要な情報を与える放射性捕獲反応に対して、その反応率を逆過程であるクーロン分解反応の断面積から求める方法が提案され、現在、分解反応による天体核反応測定の実験が本格的に開始されている。特に、星の化学組成を決めるうえで、現在、最大の不確定要因といわれている^<12>C(α,γ)^<16>Oにおいてはその直接測定がほとんど不可能と考えられているため、クーロン分解法の妥当性を検討することは重要な課題である。但し、クーロン分解反応の実験から捕獲反応の反応率を、引き出すには、核力による分解過程の寄与や反応の多段階過程の影響を精密に評価する必要がある。 本研究では、分解粒子の束縛・非束縛散乱状態をあらわに取り入れたチャネル結合法に基づき、このような分解反応の反応機構の解明、及びその断面積から天体核物理で必要となる反応の反応率を理論的に決定することを目的として研究を遂行してきた。 現在までに、微視的で現実的な^<16>O波動関数を用いたチャネル結合法により、これまでに実験測定がなされている共鳴状態への分解反応を分析、その結果、我々の理論計算が、フリーなパラメターなしに、実験結果を定量的によく説明できることを示し、この種のクーロン分解反応に、我々の微視的チャネル結合法が非常に有効であることを明らかにした。また、分析のなかみとして、核力による分解過程の寄与が非常に大きく、分解反応の実験から捕獲反応の反応率を引き出すには、我々のような分析が不可欠であることも明らかにした。現在、天体核物理で必要となる、連続状態への分解反応の分析を進めている。
• 比較的軽い原子核における分子共鳴とαクラスター鎖状構造

  日本学術振興会：科学研究費助成事業

  Date (from‐to) : 1996 -1996 

  Author : 平林 義治

   

  原子核における特徴的な存在形態の1つに分子共鳴状態がある。最近観測された^<24>Mg^*=^<12>C (0^+_2)+^<12>C (0^+_2)チャネルの分子的共鳴は、^<12>Cの0^+_2状態自身が発達した3αクラスター構造を持っていることから、6つのα粒子が鎖状に並ぶという非常に特異な構造(αクラスター鎖状構造)を示唆するのではないかと言われている。 本研究では、^<12>C+^<12>弾性・非弾性散乱に対し、微視的クラスター模型に基づく^<12>C原子核波動関数を用いたチャネル結合法により核反応自身を精密に取り扱うことにより^<24>Mg^*=^<12>C (0^+_2)+^<12>C (0^+_2)チャネルにおける分子的共鳴状態の解明を目的として研究を遂行してきた。 現在までに^<12>C (0^+_2)+^<12>C (0^+_2)チャネルの実験データ(微分断面積の角分布、断面積の励起関数)が定量的に説明できることが分かった他、本研究では^<12>C (0^+_2)+^<12>C (0^+_2)チャネル以外の多くの状態(励起状態として26状態、スキン・カップルによるサブチャネル数176チャネル)も同時に考慮し、分析を行っているが、その結果、^<12>C (0^+_2)+^<12>C (0^+_2)チャネル以外にも^<12>C (0^+_2)+^<12>C (0^+_3)、^<12>C (0^+_2)+^<12>C (3^-_1)などのチャネルに共鳴状態が存在し、これらが相関しているらしいことも判ってきた。現在、これらの幾つかの励起状態にみられる共鳴状態間の相関について詳しい分析を進めている。
• 天体熱核^<12>C(α,β)^<16>O反応のクーロン分解法による研究

  日本学術振興会：科学研究費助成事業

  Date (from‐to) : 1996 -1996 

  Author : 宇都宮 弘章, 平林 義治, 岡部 成玄, 桜井 博儀, 久保野 茂, 本林 透

   

  I.実験的研究 理研SMART磁気分析器による^<16>Oクーロン分解反応実験のために開発している,重イオン用高速MWDC検出器の次の性能を調べた。1)ヘリウム(50%)+エタン(50%)+メチラールを検出器ガスとして,放医研HIMACからの100MeV/u-αビーム,^<12>Cビームを直接照射し,スペースチャージ効果を調べた。ワイヤー1cm当たり10^5cps以上の計数率でスペースチャージ効果が認められた。2)宇宙線を測定し,最小2乗直線フィットによるレイトレーの結果,位置分解能として264μmを得た。CERNLibraryのシミュレーションプログラムGarfieldを用いて,ガス混合比とセンスワイヤー径の最適化を行なった。中間エネルギー重イオン検出の最適条件として,ガス混合比ヘリウム(30%)+エタン(70%)+メチラール,センスワイヤー直径30μm,動作カソード電圧-1600V(^<12>C),-1750V(α粒子),平均ドリフト速度4.5-4.6cm/μsecを得た。 II.理論的研究 テキサスA&M大学との共同研究により,30MeV/u-^<16>Oの2_2^+(9.84MeV),2_3^+(11.52MeV)状態を経由する分解反応の実験的反応断面積の角分布が,^<16>O-OCM波動関数を用いたチャンネル結合法によって分析された。その結果,角分布に,核力励起とクーロン励起のdestructiveな干渉に特徴的なdipが顕著に現われることが示された。中間エネルギー領域での^<16>O分解反応の定量的な理解を,今後目指す。
• 直接核反応論
• Direct Nuclear Reaction Theory