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Unified studies of light neutron-excess systems from bounds to continuum Makoto Ito Department of Pure and Applied Physics, Kansai University I. Introduction.

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Presentation on theme: "Unified studies of light neutron-excess systems from bounds to continuum Makoto Ito Department of Pure and Applied Physics, Kansai University I. Introduction."— Presentation transcript:

1 Unified studies of light neutron-excess systems from bounds to continuum Makoto Ito Department of Pure and Applied Physics, Kansai University I. Introduction II. Framework III. Various structures in 12 Be and Be isotopes - Structural changes and Reaction dynamics in Be isotopes - V. Summary and feature plan IV. Enhancements induced by level crossing

2 Molecular structures will appear close to the respective cluster threshold. α-Particle ⇒ building block Clustering phenomena is generated by a huge mixing of shell model configuration. 3 H+p ~ 20 MeV Cluster structures in 4N nuclei IKEDA Diagram Ikeda’s Threshold rules Be isotopes Molecular Orbital : Itagaki et al,…. ― ― + + PRC61,62 (2000) H.O. quanta N ±  N ~ 34.6 ± 5.9

3 Studies on Exotic Nuclear Systems in (E x,N, Z,J) Space ( N,Z ) : Two Dimensions Ex. energy Structural Change Low-lying Molecular Orbital :  ― 、  + ‥ Unbound Nuclear Systems Slow RI beam Decays in Continuum Is Threshold Rule valid ?? N 1. Structures of 8 ~ 16 Be 2. Breakup of 10,12 Be

4 Extension of microscopic cluster model (Test calculation for 10 Be) Unified model between M.O. and He clusters :PLB588 (04) C1 C2C3  0Pi (i=x,y,z) Coupled channels with Atomic orbitals Mol. Orb.  6 He Decay widh PTP113 (05)  + 6 He Cross sections PLB636 (06) 10 Be=  +  +N+N ー i W(R) S, Ci : Variational PRM. S 5 He Combine Absorbing B.C.Scattering B.C.Tr. densites 10 Be  →  + 6 He Breakup

5 Femto Molecules : 12 Be=  +  +4N 7 He 5 He 6 He 8 He 6 He Ionic Atomic Neutrons’ ex. (-)2(-)2 (-)2(-)2 (  - ) 2 (  + ) 2 (0p R )(0p L ) (  + )  + 8 He ⇒ 6 He+ 6 He Covalent 6 He + 6 He  + 8 He Clusters’ Relative ex. Various structures are generated by excitation of  -  and neutron degree of freedom. NN: Volkov No.2+G3RS

6 Be isotopes from bounds to continuums : J  = Be 10 Be 12 Be 14 Be 16 Be Deformed states (Clusters) Compact states (Shell model) Excitation of  -  rel. motion x He y He

7 Level Crossings scheme in Be isotopes Core-Core distance LargeSmall A + B C + D Energy Compact ( Normal ) Clusters ( Intruder ) Internal States Asymptotic States Level Crossing We can discuss reaction dynamics in connection to level crossing scheme.

8  + 6 He g.s. 8 He g.s. + 6 He g.s. 10 Be 14 Be Level Crossings in 12,14 Be=  +  +XN (X=2,6) (0p) 2 (sd) 2 (0p) 4 (sd) 2 (0p) 2 (sd) 4 Level Crossing

9 Adiabatic surfaces (J  = 0 + ) Energy spectra ( J  = 0 + ) ー i W(R)  + 6 He(2 1 + ) GTCM + Absorbing Boundary Condition : PLB (2006) Cluster

10 S-matrices to continuums Smat.( Poles ← G.S.)Smat.( Conti.←G.S. ) Nuclea breakup : 10 Be + 12 C ⇒ 10 Be(0 + conti.) + 12 C (CDCC cal.) S-matrices to Poles

11 Non-adiabatic tr. is main process. Reaction path in 10 Be → x He + y He Breakup reaction (Positive Parity) × → is the dominant transition. 10 Be(0 + ) → [  + 6 He(2 1 + ) ] 0 + Reaction Path in Breakup

12 Level Crossing in 12 Be (2) : breaking of N=8 magic number and level crossing Correlated AESsAESs with full coupling Coupling with all configurations Lowest minimum smoothly connected to  + 8 He g.s. ⇒ Formation of adiabatic conjunction Conjunction G.S. ⇔  + 8 He  + 8 He g.s. G.S. (  - ) 2 (  + ) 2 (  - ) 2 (  - ) 2  + 8 He g.s. [(0p) 6 ] [(0p) 4 (sd) 2 ] Correlation

13 Monopole transition of 12 Be Adiabatic transition is main process in monopole transition. (  - ) 2 (  + ) 2 8 He → is enhanced.

14 Contents of present report Results 1. Unified studies form bounds to continuums in Be isotopes Feature studies Extension to SD shell ⇒ O=  + 12 C+XN 、 Ne=  + 16 O+XN Generalities and Specialities : hybrid structures of clusters + excess neutrons in O and Ne 2. Reactions with large amplitudes in connection to adiabatic energy surfaces 1. There appears a wide variety of structures in excited states (Cluster + excess N) 2. Enhancements occur depending on the structures of AESs. 10 Be : Non-adiabatic path is dominant in monopole breakup. 12 Be : Adiabatic path is dominant in monopole breakup (breaking of N=8 magic). Recently, we have just succeeded in extending the model to general two centers.


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