1998 Fiscal Year Annual Research Report

ストレンジネス原子核の理論的研究

Research Project

Project/Area Number	08239104
Research Category	Grant-in-Aid for Scientific Research on Priority Areas (A)
Research Institution	OSAKA ELECTRO-COMMUNICATION UNIVERSITY
Principal Investigator	元場俊雄大阪電気通信大学, 工学部, 教授 (90121863)
Co-Investigator(Kenkyū-buntansha)	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)
Keywords	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
Research Abstract	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.

Research Products
(33 results)

All Other

All Publications (33 results)

[Publications] T.Motoba: "New aspects of hypernuclear structure" Nuclear Physics. A629. 398c-404c (1998)
[Publications] 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)
[Publications] T.Motoba: "Parity-mixing intershell couplingin hypernuclei and properties ΛN interactions" Nuclear Physics. A639. 135c-146c (1998)
[Publications] S.Ajimura et al.: "Polarization of^5_ΛHe produced by the(π^+,K^+)reaction" Physical Review Letters. 80. 3471-3474 (1998)
[Publications] 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)
[Publications] M.Sotona,et al.: "Electroproduction of strangeness and hypernuclear spectroscopy" Proc.Mesons and Light Nuclei:Few Body Systems. (1999)
[Publications] 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)
[Publications] T.Harada: "Theoretical analysis of the ^4He(K^-,π^<【minus-plus】>)spectrum" Nuclear Physics. A631. 771c-775c (1998)
[Publications] T.Harada: "Strangeness exchange reactions on a helium target" Nuclear Physics. A638. 185c-188c (1998)
[Publications] T.Myo etal.: "Resonance and Continuum Components of the Strength Function" Prog.Theor.Phys.99. 801-817 (1998)
[Publications] 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)
[Publications] 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)
[Publications] A.Ohnishi,et al.: "Quantum Fluctuation Effects on Nuclear and Atomic Cluster Formation" Nucl.Phys.A630. 223c-230c (1998)
[Publications] Y.Hirata,et al.: "Formation of twin and double hypernuclei from Ξ^- absorption at rest on ^<12>C" Nucl.Phys.A639. 389c-392c (1998)
[Publications] 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)
[Publications] 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)
[Publications] 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)
[Publications] A.Ohnishi,et al.: "Can We Extract Lambda-Lambda Interaction from Two-Particle Momentum Corre-lation?" Nucl.Phys.A. (1999)
[Publications] M.Oka: "π^+ Emission from Hypernuclei and the Weak ΔI=3/2 Transitions" Nuclear Physics. A. (1999)
[Publications] M.Oka: "Roles of Quark Degrees of Freedom in Hypernuclei" Nuclear Physics. A629. 379c-387c (1998)
[Publications] 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)
[Publications] M.Oka: "QCD Nuclear Physics" Proc.Intern.Workshop on JHF Science,KEK Proceedings. 98-5 I. 61-70 (1998)
[Publications] M.Oka: "Direct Quark Mechanism for Weak ΛN【reverse surface chemistry " Proc.APCTP Workshop on Astro-Hadron Physics: Properties of Hadrons in Matter. (1997)
[Publications] M.Oka,et al.: "Roles of Quarks in Strong and Weak YN Interactions" Proc.Mesons and Light Nuclei: Few Body Systems. (1999)
[Publications] T.Ueda,et al.: "ΛN and ΛΛ Interactions in an OBE Model and Hypernuclei" Progress of Theoretical Physics. 99. 891-896 (1998)
[Publications] 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)
[Publications] K.Tominaga et al.: "An One-Boson-Exchange Potential for ΛN,ΛΛ and ΞN Systems and Hypernuclei" Nuclear Physics. A642. 483-505 (1998)
[Publications] 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)
[Publications] Y.Yamamoto: "Production of double-Λ hypernuclei at(K^-,K^+)reaction points" Nuclear Physics. A639. 393c-396c (1998)
[Publications] 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)
[Publications] Th.A.Rijken,et al.: "Soft-core hyperon-nucleon potentials" Physical Review. C59. 21-40 (1999)
[Publications] 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)
[Publications] 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 Fiscal Year Annual Research Report

ストレンジネス原子核の理論的研究

Principal Investigator

元場 俊雄 大阪電気通信大学, 工学部, 教授 (90121863)

Research Products

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

[Publications] 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)

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

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

[Publications] 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)

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

[Publications] 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)

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

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

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

[Publications] 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)

[Publications] 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)

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

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

[Publications] 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)

[Publications] 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)

[Publications] 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)

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

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

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

[Publications] 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)

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

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

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

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

[Publications] 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)

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

[Publications] 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)

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

[Publications] 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)

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

[Publications] 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)

[Publications] 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)

元場俊雄大阪電気通信大学, 工学部, 教授 (90121863)