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2001 Fiscal Year Final Research Report Summary

Theoretical study of antiproton and position collisions related to antimatter physics

Research Project

Project/Area Number 11640384
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 物理学一般
Research InstitutionUniversity of Tsukuba

Principal Investigator

TOSHIMA Nobuyuki  University of Tsukuba, Inst. Materials Science, Professor, 物質工学系, 教授 (10134488)

Co-Investigator(Kenkyū-buntansha) IGARASHI Akinori  Miyazaki University, Fac. Engineering, Reseach Associate, 工学部, 助手 (90300855)
Project Period (FY) 1999 – 2001
Keywordsantiproton / positron / antimatter / atomic collision
Research Abstract

Complex structures of cross sections are sometimes induced by resonance phenomena in positron scatterings by atoms. Comparison with the results for electron scatterings give detailed information on the electronic properties interactions of atoms. We investigated the basic physics of the resonance scatterings of positrons in terms of large-scale hypersherical close-coupling calculations. The present method remedies the defects of existing old theories which use insufficient number of atomic orbitals for the expansion.
Most of theoretical works on antiproton collisions with hydrogen atoms are based on the one-center atomic orbital expansion. However, we can expect that the electronic clouds are distorted considerably in the neighborhood of the antiproton owing to the repulsive Coulomb interaction. A large-scale two-center expansion was employed to study this effect and it was found that the distribution of the electron is really evacuated near the antiproton. Traditional one-center expansions can not represent such local distribution properly.
At low energies where the average velocity of the electron is much larger than the incident velocity of the antiproton, the electron flistribution spreads up to several hundred atomic units when the collision has finished. Such diffuse electronic states can not be adequately represented by bound-type basis functions such as the Slater or the Gaussian orbitals. In order to solve this difficulty we introduced B-spline expansion to the low-energy scatterings. The B-splines are piecewise polynomials which are continuous up to some degree of derivatives at the borders. The B-spline expansion gives 20 % larger ionization cross sections than the bound-type expansions.

  • Research Products

    (24 results)

All Other

All Publications (24 results)

  • [Publications] J.Eichler, Y.Yoshihama, N.Toshima: "Axial and Landau gause for a continuum electron in a homogeneous magnetic field"Physical Review A. 65. 33404.1-33404.6 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] J.Azuma, N.Toshima, K.Hino, A.Igarashi: "B-spline expansion of scattering equations for ionization of atomic hydrogen by antiproton impact"Physical Review A. 64. 62704.1-62704.9 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] N.Toshima: "Two-and one-center close-coupling calculations for ionization of atomic hydrogen by antiproton impact"Physical Review A. 64. 24701.1-24701.4 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] A.Igarashi, A.Ohsaki, S.Nakazaki: "Cross sections for electron detachment of the hydrogen negative ion and for single ionization of helium by antiproton impact"Physical Review A. 64. 42717.1-42717.4 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] A.Igarashi, I.Shimamura, N.Toshima: "Photodetachment cross sections of the positronium negative ion"New Journal of Physics. 2. 17.1-17.14 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] A.Igarashi, A.Ohsaki, S.Nakazaki: "Single ionization of helium by antiproton impact"Physical Review A. 62. 52722.1-52722.5 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Z.X.Zhao, A.Igarashi, C.D.Lin: "Hyperspherical calculations of H(1s)+μ^+ rearrangement cross sections from threshold to 2 eV"Physical Review A. 62. 42706.1-42706.5 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] A.Igarashi, S.Nakazaki, A.Ohsaki: "Ionization of atomic hydrogen by antiproton impact"Physical Review A. 61. 62714.1-62714.5 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] N.Toshima: "Detailed comparison of capture probabilities between the close-coupling of method and high-energy distorted-wave theories"Journal of Physics B. 32. L615-L620 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] N.Toshima: "Convergence and completeness of the pseudostate expansion for proton-hydrogen collisions in two-center close-coupling calculations"Physical Review A. 59. 1981-1987 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] N.Toshima, T.Nakagawa: "Coupled-channel eikonal approach to electron capture"Physical Review A. 60. 2182-2185 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] A.Igarashi, C.D.Lin: "Full ambiguity-free quantum treatment of D^++H(1s) charge transfer reactions at low energies"Physical Review Letters. 83. 4041-4044 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] J. Eichler, Y. Yoshihama, N. Toshima: "Axial and Landau gauge for a continuum electron in a homogeneous magnetic field"Phisical Review A. 65. 33404.1-6 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] J. Azuma, N. Toshima, K.Hino, A. Igarashi: "B-spline expansion of scattering equations for ionization of atomic hydrogen by antiproton impact"Phisical Review A. 64. 62704.1-9 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] N. Toshima: "Two- and one-center close-coupling calculations for ionization of atomic hydrogen by antiproton impact"Phisical Review A. 64. 24701.1-4 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] A. Igarashi, A. Ohsaki, S. Nakazaki: "Cross sections for electron detachment of the hydrogen negative ion and for single ionization of helium by antiproton impact"Phisical Review A. 64. 42717.1-4 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] A. Igarashi, I. Shimamura, N. Toshima: "Photodetachment cross sections of the positronium negative ion"New Journal of Physics. 2. 17.1-17.14 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] A. Igarashi, A. Ohsaki, S. Nakazaki: "Single ionization of helium by antiproton impact"Phisical Review A. 62. 52722.1-5 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Z.X. Zhao, A. Igarashi, C.D. Lin: "Hyperspherical calculations of H(1s) +μ^+ rearrangement cross sections from threshold to 2 eV"Phisical Review A. 62. 42706.1-5 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] A. Igarashi, S. Nakazaki, A. Ohsaki: "Ionization of atomic hydrogen by antiproton impact"Phisical Review A. 61. 62714.1-5 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] N. Toshima: "Detailed comparison of capture probabilities between the close-coupling method and high-energy distorted-wave theories"Phisical Review B. 32. L615-L620 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] N. Toshima: "Convergence and completeness of the pseudostate expansion for proton-hydrogen collisions in two-center close-coupling calculations"Phisical Review A. 59. 1981-1987 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] N. Toshima, T. Nakagawa: "Coupled-channel approach to electron capture"Phisical Review A. 60. 2182-2185 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] A. Igarashi, C.D. Lin: "Full ambiguity-free quantum treatment of D +(Hls) charge trans fer reactions at low energies"Physical Review Letters. 83. 4041-4044 (1999)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2003-09-17  

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