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YN/YY 相互作用とハイパー核 ΞN interaction をめぐって

YN/YY 相互作用とハイパー核 ΞN interaction をめぐって. 2007/3/2 伊勢志摩. Y. Yamamoto Tsuru University. 核力から核構造・反応へ. 核物理の原点 ・ Shell model の成立 ・ BBG theory. G-matrix. lowest order. G-matrix theory は核物理における確立した基礎理論 有用なツール. Nuclear Saturation Problem は基本的には解決済み. Nuclear saturation curve for ESC04. 中性子星.

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YN/YY 相互作用とハイパー核 ΞN interaction をめぐって

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  1. YN/YY 相互作用とハイパー核ΞN interactionをめぐって 2007/3/2 伊勢志摩 Y. Yamamoto Tsuru University

  2. 核力から核構造・反応へ 核物理の原点 ・Shell model の成立 ・BBG theory G-matrix lowest order G-matrix theory は核物理における確立した基礎理論 有用なツール Nuclear Saturation Problemは基本的には解決済み

  3. Nuclear saturation curve for ESC04 中性子星 including MIR Fujita-Miyazawa MIR is quite similar to Illinois-TBR

  4. Nucleon optical potential Hyperon-nucleus potential derived in the same framework from underlying BB interactions 背景に同じ物理がある 核力　　　G-matrix interaction folding

  5. 核力から核構造 YN/YY hypernuclei 本当の意味は？ bare interactionを使って計算すれば良いということではない！

  6. 玉垣さんのテキストより π π

  7. 核力の特性とメソンの役割 ● OPEP tail π ● 領域Ⅱの強い引力　“σ” ● テンソル力　π-ρ ● LS力　“σ”+ω+ρ ● repulsive core 原子核の性質 QM core ? 領域Ⅲの性質は顕著には現れない（ひっそりと支える） テンソル力は２次項が支配的役割

  8. 原子核におけるπもしくはテンソル力 dominant roles “σ”の実体、３体力 saturation のコントロール minor roles OPEP tail effective tensor による weak mixing

  9. by 玉垣さん 2000/7 Before NAGARA 2π-exchange via Δ-excitation Fujita-Miyazawa TBF σ-meson の実体 ΛΛ引力は弱い 核力における 引力の主要項 ESCではpair terms

  10. ESC modeling PS, S, V, AV nonets not taken (ππ),(πρ),(πω),(πη),(σσ) PS-PS exchange

  11. 領域Ⅲ Repulsive core の成因 ESCポメロン+ωチャネル・状態依存性はあまりない FSS/fss2 QMに特有のチャネル依存性がある ハイパー核で領域Ⅲを見れるか？ 実はESC04の顕著な特質は r<1 fm に依拠している heavy mesons Region Ⅲ = repulsive core ではない !?　豊かな物理?

  12. ハイパー核物理の目標 Λ核の諸特性、Σ核、ΛΛ核、Ξ核 ・・・ 多様な存在形態を相互作用の特質 (mesons & core)と関連付けて 統一的に理解すること S=0系には登場しない多彩なメソンの役割は？ 領域Ⅲの特質はいかに発現するか？

  13. YN/YY相互作用の研究は ストレンジネス多体系の新たな質の 発見と連動する現在進行形である ESC-modelingにおける新たな実体 （多様なpair terms、AV mesons) の導入は、その方向に沿った試みである attractive UΞ、 repulsive UΣ、small s.o. splitting

  14. BNL-E885 Motoba’s calculation U0～ -14 MeV

  15. KEK-E176 P-state nuclear bound state UΞ～ -16 MeV

  16. Our methodology ① Study of Ξ hypernuclei/ΞN interaction is in a phenomenological stage (現象論的段階） ② Our starting point is to consider the experimental suggestions of attractive UΞ(～ -14MeV) as a working assumption (作業仮説） ③ ΞN interaction models giving rise to attractive UΞ are investigated through structure calculations for Ξ hypernuclei

  17. まずは古い話から・・・ Special modeling in ND related to attractive ΞN interaction not taken

  18. ΞN NN

  19. No space-exchange component in VΞN(OBE) because S=-2 cannot be carried by a boson

  20. NHC-F NSC89 NSC97 A longstanding model giving attractive UΞ NHC-D repulsive! Special modeling to include only singlet scalar meson (σ) Another possibility ESC04d What difference from NHC-D ?

  21. Extended Soft-Core Model ESC0４ Phys. Rev. C73, 044008 (2006) ●Two-meson exchange processes are treated explicitly no effective bosons are used ●PS, S, V, AV meson-nonets are taken into account ●Meson-Baryon coupling constants are consistent with Quark-model predictions Parameter fitting G-matrix Hypernuclear data not only YN scattering data

  22. Different predictions for Ξ hypernuclear states most interesting for Ξstates From the particle-physics point of view ESC04d is favored 1. pv-coupling for the pseudo-scalar mesons 2. SU3-symmetry for the couplings

  23. ESC04 ESC06 Too complicated ???

  24. ΛΛ phase shifts Old data Pair Nagara

  25. coupling diagonal Total OBE Pair Total （repulsion） Pair Strong ΛΛ-ΞN coupling from Pair terms

  26. Strong ΞＮ-ΛΛ coupling Exp ~ 1.0 ESC04 models are consistent with NAGARA data

  27. Strong 13S1 attraction ! strong P-state attraction Adjustable parts: ESC04 Medium-induced repulsion NHC-D Hard-core radius

  28. Specific bound states in 2-,3-,4-body systems

  29. Pair OBE Total On the other hand ΛN: Pair attractive OBE repulsive

  30. OBE repulsive Pair attractive ΛＮ 　case Canceling of Scalar and Vector V V S S

  31. OBE attraction in ΞＮ 13S1 state PS V ω Canceling of V and AV Attraction of S appears cancel S AV ε attractive a1

  32. A folding model for Ξ-hypernuclei including imaginary part Density-dependent G-matrix interaction Lane term

  33. (standard in derivations of optical potential)

  34. Ξ-+closed-core systems adjusted Mass-dependence Conversion width Note!

  35. with ESC04d Lane term ~ (N-Z+1)/4 available (K-,K+) N=Z cores N>Z cores (K-,K0) Ξ hypernuclei produced by (K-,K+) reactions on available targets

  36. Features of ESC04d and NHC-D ESC04d NHC-D Mass-dep of BΞweakstrong Lane termstrongweak light Ξ-states○× Conversion widthlargesmall

  37. In the case of FSS/fss2

  38. Conclusion （ESC04 and Ξhypernuclei） A ”solution” ofESC04 modeling leads to attractive UΞ U0≒-14 MeV(if true) is realized by strong 13S1 attraction in ESC04 model There exist some s-shell Ξ-bound states dominated by 13S1 components Conversion width ΓΞ is large due to strong ΞN-ΛΛ coupling in 11S0 state These features are completely different from FSS/fss2 models!!!

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