1998 年度実績報告書

ストレンジネス原子核の理論的研究

研究課題

研究課題/領域番号	08239104
研究種目	特定領域研究(A)
研究機関	大阪電気通信大学
研究代表者	元場俊雄大阪電気通信大学, 工学部, 教授 (90121863)
研究分担者	糸永一憲宮崎医科大学, 医学部, 教授 (90029546) 山本安夫都留文科大学, 文学部, 教授 (80124866) 岡真東京工業大学, 理学部, 教授 (60144606) 矢崎紘一東京大学大学院, 理学系研究科, 教授 (60012382) 赤石義紀高エネルギ加速器研究機構, 素核研, 教授 (50001839)
キーワード	ハイパー原子核 / ハイペロン核子相互作用 / 非中間子型弱崩壊 / ハイパー核寿命 / ストレンジネス・ハロー / ダブルハイパー核 / H粒子
研究概要	研究計画に対応して主な実績を概説する: (1)少数系からp殻をふくむ軽いΛハイパー核の精密計算と,LS力やodd成分やσ_Λ・σ_N成分の役割が明らかにされた.これとの関連でNijmegenグループと協力して新しいOBE模型核力を提案した.重いハイパー核では有効質量や一粒子軌道分離とYN核力の関連性を明確にした.また,(e,e'K+),(γ,K+)反応の強度関数が計算されて中重核で有用であることが示された. (2)^7Liなど典型核でΛによる芯核の収縮の理論が最近のγ線データにより確証された. (3)飛翔K^-実験により明らかになった^4_ΣHeの束縛状態について,Λ-Σチャネルを結合させた枠組みで詳細な理論的解析を行い,その状態の準位と幅を確定した. (4)strangeness-2のハイパー核については,hyperon混合が状態依存的であり,励起状態(^sΛpΛ)で混合が大きくなること,またクオーク模型RGM-F相互作用ではΛΛ-ΞN-ΣΣ結合の効果は一般に強くなる傾向が明らかされた.(4)生成率については,直接反応に引き続き微視的輸送理論が適用されて,Ξ状態からシングルおよびツインやダブルハイパー核生成に至る詳細な結果を得た.また,生成反応の終状態相関からΛΛ相互作用を引き出す試みがなされた.(5)quark模型によるbaryon間相互作用理論を発展させて,HNおよびHH相互作用のquark模型による計算で斥力引力効果を調べ,H物質の可能性を調べた.(6)非中間子型弱崩壊については,Direct Quark過程による崩壊振幅の計算により,特にJ=0ではΔI=3/2遷移の重要な役割を明らかにし,中性子と陽子誘起崩壊比も改善の方向が得られることを示した.またカレント代数の方法を用いて,π^+放出の崩壊過程がΔI=3/2の非中間子崩壊と強く関連していることを指摘した.(7)他方においては,1π交換の次のオーダーの相関2πの交換として,2π/ρ及び2π/σ交換過程による弱崩壊相互作用を理論的に評価し,軽い核のΓnmを説明出来ること,Γn/Γpは0.3-0.4程度の改善を与えることから,これらの相互作用は重要であることを示した.同時に,中重ハイパー核寿命の実験データを約15%以内の違いで説明できることを示した.

研究成果

(33件)

すべてその他

すべて文献書誌 (33件)

[文献書誌] T.Motoba: "New aspects of hypernuclear structure" Nuclear Physics. A629. 398c-404c (1998)
[文献書誌] T.Inoue et al.: "Non-mesonic weak decays of light hypernuclei in the direct quark and the one-pion exchange mechanisms" Nuclear Physics. A633. 312-330 (1998)
[文献書誌] T.Motoba: "Parity-mixing intershell couplingin hypernuclei and properties ΛN interactions" Nuclear Physics. A639. 135c-146c (1998)
[文献書誌] S.Ajimura et al.: "Polarization of^5_ΛHe produced by the(π^+,K^+)reaction" Physical Review Letters. 80. 3471-3474 (1998)
[文献書誌] T.Motoba et al.: "Pionic weak decay of S=-2 hypernuclei" Proc.Sendai Intern.Workshop on the Spectroscopy of Hypernuclei,原子核研究. 43. 169-180 (1998)
[文献書誌] M.Sotona,et al.: "Electroproduction of strangeness and hypernuclear spectroscopy" Proc.Mesons and Light Nuclei:Few Body Systems. (1999)
[文献書誌] Toru Harada: "Calculation of the ^4_ΣHe bound state in the ^4He(K^-,π^-)reaction at 600 MeV/c" Physical Review Letters. 81. 5287-5290 (1998)
[文献書誌] T.Harada: "Theoretical analysis of the ^4He(K^-,π^<【minus-plus】>)spectrum" Nuclear Physics. A631. 771c-775c (1998)
[文献書誌] T.Harada: "Strangeness exchange reactions on a helium target" Nuclear Physics. A638. 185c-188c (1998)
[文献書誌] T.Myo etal.: "Resonance and Continuum Components of the Strength Function" Prog.Theor.Phys.99. 801-817 (1998)
[文献書誌] Y.Nara,et al.: "Study of(K^-,K^+)Reactions within the Quantum Molecular Dynamics Approach" Proc.25th INS Intern.Symp.on Nuclear and Particle Physics with High-Intensity Proton Accelerators(World Sci.). 324-329 (1998)
[文献書誌] N.Ohtsuka,et al.: "Thermodynamical Evolution of Hot and Dense Hadronic Matter from Intranuclear Cascade Simulation" Proc.25th INS Intern.Symp.on Nuclear and Particle Physics with High-Intensity Proton Accelerators(World Sci.). 415-416 (1998)
[文献書誌] A.Ohnishi,et al.: "Quantum Fluctuation Effects on Nuclear and Atomic Cluster Formation" Nucl.Phys.A630. 223c-230c (1998)
[文献書誌] Y.Hirata,et al.: "Formation of twin and double hypernuclei from Ξ^- absorption at rest on ^<12>C" Nucl.Phys.A639. 389c-392c (1998)
[文献書誌] A.Ohnishi et al.: "Molecular dynamics with quantum fluctuations and its application to heavy ion col-lisions" Proc.the XVII RCNP Int.Symp.Innovative Computational Meth-ods in Nuclear Many-Body Problems(World Sci.). 470-474 (1998)
[文献書誌] Y.Hirata,et al.: "Effects of Quantum Fluctuations in Antisymmetrized Molecular Dynamics" Proc.the XVII RCNP Int.Symp.Innovative Computational Meth-ods in Nuclear Many-Body Problems(World Sci.). 475-477 (1998)
[文献書誌] N.Otuka,et al.: "The Role of Higher Excited Baryonic Resonances in Heavy Ion Collisions at AGS Energies" Proc.the XVII RCNP Int.Symp.Innovative Computational Meth-ods in Nuclear Many-Body Problems(World Sci.). 495-497 (1998)
[文献書誌] A.Ohnishi,et al.: "Can We Extract Lambda-Lambda Interaction from Two-Particle Momentum Corre-lation?" Nucl.Phys.A. (1999)
[文献書誌] M.Oka: "π^+ Emission from Hypernuclei and the Weak ΔI=3/2 Transitions" Nuclear Physics. A. (1999)
[文献書誌] M.Oka: "Roles of Quark Degrees of Freedom in Hypernuclei" Nuclear Physics. A629. 379c-387c (1998)
[文献書誌] M.Oka: "QCD Aspects of Strangeness Nuclear Physics and Hypernuclei" Proc.Sendai Intern.Workshop on the Spectroscopy of Hypernuclei,原子核研究. 43. 1-10 (1998)
[文献書誌] M.Oka: "QCD Nuclear Physics" Proc.Intern.Workshop on JHF Science,KEK Proceedings. 98-5 I. 61-70 (1998)
[文献書誌] M.Oka: "Direct Quark Mechanism for Weak ΛN【reverse surface chemistry " Proc.APCTP Workshop on Astro-Hadron Physics: Properties of Hadrons in Matter. (1997)
[文献書誌] M.Oka,et al.: "Roles of Quarks in Strong and Weak YN Interactions" Proc.Mesons and Light Nuclei: Few Body Systems. (1999)
[文献書誌] T.Ueda,et al.: "ΛN and ΛΛ Interactions in an OBE Model and Hypernuclei" Progress of Theoretical Physics. 99. 891-896 (1998)
[文献書誌] T.Yamada: "Production of double-Λ,single-Λ and twin Λ hypernuclei from ^<12>C+Ξ^- atomic states in the direct reaction picture" Nuclear Physics. A639. 385c-388c (1998)
[文献書誌] K.Tominaga et al.: "An One-Boson-Exchange Potential for ΛN,ΛΛ and ΞN Systems and Hypernuclei" Nuclear Physics. A642. 483-505 (1998)
[文献書誌] K.Kato,et al.: "Dynamical Effects on the ^9Li-n Interaction Induced by Pauli Blocking of J^π=O^+ Pairing Correlation" Progress of Theoretical Physics. 101. 119-138 (1999)
[文献書誌] Y.Yamamoto: "Production of double-Λ hypernuclei at(K^-,K^+)reaction points" Nuclear Physics. A639. 393c-396c (1998)
[文献書誌] Y.Yamamoto: "Baryon-Baryon Interaction and Hypernuclear Spectroscopy" Proc.Sendai Intern.Workshop on the Spectroscopy of Hypernuclei,原子核研究. 43-4. 17-26 (1998)
[文献書誌] Th.A.Rijken,et al.: "Soft-core hyperon-nucleon potentials" Physical Review. C59. 21-40 (1999)
[文献書誌] K.Itonaga,et al.: "Nonmesonic Decay Rates and Lifetimes of Light-to-Medium Λ-Hypernuclei" Proc.25th INS Intern.Symp. Nuclear and Particle Physics with High-Intensity Proton Accelerators(World Sci.). 489-490 (1998)
[文献書誌] K.Itonaga,et al.: "A-dependence of non-mesonic decay rates in the 1π and correlated 2π exchange model" Nuclear Physics. A639. 329c-332c (1998)

1998 年度 実績報告書

ストレンジネス原子核の理論的研究

研究代表者

元場 俊雄 大阪電気通信大学, 工学部, 教授 (90121863)

研究成果

[文献書誌] T.Motoba: "New aspects of hypernuclear structure" Nuclear Physics. A629. 398c-404c (1998)

[文献書誌] T.Inoue et al.: "Non-mesonic weak decays of light hypernuclei in the direct quark and the one-pion exchange mechanisms" Nuclear Physics. A633. 312-330 (1998)

[文献書誌] T.Motoba: "Parity-mixing intershell couplingin hypernuclei and properties ΛN interactions" Nuclear Physics. A639. 135c-146c (1998)

[文献書誌] S.Ajimura et al.: "Polarization of^5_ΛHe produced by the(π^+,K^+)reaction" Physical Review Letters. 80. 3471-3474 (1998)

[文献書誌] T.Motoba et al.: "Pionic weak decay of S=-2 hypernuclei" Proc.Sendai Intern.Workshop on the Spectroscopy of Hypernuclei,原子核研究. 43. 169-180 (1998)

[文献書誌] M.Sotona,et al.: "Electroproduction of strangeness and hypernuclear spectroscopy" Proc.Mesons and Light Nuclei:Few Body Systems. (1999)

[文献書誌] Toru Harada: "Calculation of the ^4_ΣHe bound state in the ^4He(K^-,π^-)reaction at 600 MeV/c" Physical Review Letters. 81. 5287-5290 (1998)

[文献書誌] T.Harada: "Theoretical analysis of the ^4He(K^-,π^<【minus-plus】>)spectrum" Nuclear Physics. A631. 771c-775c (1998)

[文献書誌] T.Harada: "Strangeness exchange reactions on a helium target" Nuclear Physics. A638. 185c-188c (1998)

[文献書誌] T.Myo etal.: "Resonance and Continuum Components of the Strength Function" Prog.Theor.Phys.99. 801-817 (1998)

[文献書誌] Y.Nara,et al.: "Study of(K^-,K^+)Reactions within the Quantum Molecular Dynamics Approach" Proc.25th INS Intern.Symp.on Nuclear and Particle Physics with High-Intensity Proton Accelerators(World Sci.). 324-329 (1998)

[文献書誌] N.Ohtsuka,et al.: "Thermodynamical Evolution of Hot and Dense Hadronic Matter from Intranuclear Cascade Simulation" Proc.25th INS Intern.Symp.on Nuclear and Particle Physics with High-Intensity Proton Accelerators(World Sci.). 415-416 (1998)

[文献書誌] A.Ohnishi,et al.: "Quantum Fluctuation Effects on Nuclear and Atomic Cluster Formation" Nucl.Phys.A630. 223c-230c (1998)

[文献書誌] Y.Hirata,et al.: "Formation of twin and double hypernuclei from Ξ^- absorption at rest on ^<12>C" Nucl.Phys.A639. 389c-392c (1998)

[文献書誌] A.Ohnishi et al.: "Molecular dynamics with quantum fluctuations and its application to heavy ion col-lisions" Proc.the XVII RCNP Int.Symp.Innovative Computational Meth-ods in Nuclear Many-Body Problems(World Sci.). 470-474 (1998)

[文献書誌] Y.Hirata,et al.: "Effects of Quantum Fluctuations in Antisymmetrized Molecular Dynamics" Proc.the XVII RCNP Int.Symp.Innovative Computational Meth-ods in Nuclear Many-Body Problems(World Sci.). 475-477 (1998)

[文献書誌] N.Otuka,et al.: "The Role of Higher Excited Baryonic Resonances in Heavy Ion Collisions at AGS Energies" Proc.the XVII RCNP Int.Symp.Innovative Computational Meth-ods in Nuclear Many-Body Problems(World Sci.). 495-497 (1998)

[文献書誌] A.Ohnishi,et al.: "Can We Extract Lambda-Lambda Interaction from Two-Particle Momentum Corre-lation?" Nucl.Phys.A. (1999)

[文献書誌] M.Oka: "π^+ Emission from Hypernuclei and the Weak ΔI=3/2 Transitions" Nuclear Physics. A. (1999)

[文献書誌] M.Oka: "Roles of Quark Degrees of Freedom in Hypernuclei" Nuclear Physics. A629. 379c-387c (1998)

[文献書誌] M.Oka: "QCD Aspects of Strangeness Nuclear Physics and Hypernuclei" Proc.Sendai Intern.Workshop on the Spectroscopy of Hypernuclei,原子核研究. 43. 1-10 (1998)

[文献書誌] M.Oka: "QCD Nuclear Physics" Proc.Intern.Workshop on JHF Science,KEK Proceedings. 98-5 I. 61-70 (1998)

[文献書誌] M.Oka: "Direct Quark Mechanism for Weak ΛN【reverse surface chemistry " Proc.APCTP Workshop on Astro-Hadron Physics: Properties of Hadrons in Matter. (1997)

[文献書誌] M.Oka,et al.: "Roles of Quarks in Strong and Weak YN Interactions" Proc.Mesons and Light Nuclei: Few Body Systems. (1999)

[文献書誌] T.Ueda,et al.: "ΛN and ΛΛ Interactions in an OBE Model and Hypernuclei" Progress of Theoretical Physics. 99. 891-896 (1998)

[文献書誌] T.Yamada: "Production of double-Λ,single-Λ and twin Λ hypernuclei from ^<12>C+Ξ^- atomic states in the direct reaction picture" Nuclear Physics. A639. 385c-388c (1998)

[文献書誌] K.Tominaga et al.: "An One-Boson-Exchange Potential for ΛN,ΛΛ and ΞN Systems and Hypernuclei" Nuclear Physics. A642. 483-505 (1998)

[文献書誌] K.Kato,et al.: "Dynamical Effects on the ^9Li-n Interaction Induced by Pauli Blocking of J^π=O^+ Pairing Correlation" Progress of Theoretical Physics. 101. 119-138 (1999)

[文献書誌] Y.Yamamoto: "Production of double-Λ hypernuclei at(K^-,K^+)reaction points" Nuclear Physics. A639. 393c-396c (1998)

[文献書誌] Y.Yamamoto: "Baryon-Baryon Interaction and Hypernuclear Spectroscopy" Proc.Sendai Intern.Workshop on the Spectroscopy of Hypernuclei,原子核研究. 43-4. 17-26 (1998)

[文献書誌] Th.A.Rijken,et al.: "Soft-core hyperon-nucleon potentials" Physical Review. C59. 21-40 (1999)

[文献書誌] K.Itonaga,et al.: "Nonmesonic Decay Rates and Lifetimes of Light-to-Medium Λ-Hypernuclei" Proc.25th INS Intern.Symp. Nuclear and Particle Physics with High-Intensity Proton Accelerators(World Sci.). 489-490 (1998)

[文献書誌] K.Itonaga,et al.: "A-dependence of non-mesonic decay rates in the 1π and correlated 2π exchange model" Nuclear Physics. A639. 329c-332c (1998)

1998 年度実績報告書

元場俊雄大阪電気通信大学, 工学部, 教授 (90121863)