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ISOVECTOR EXCITATIONS OF sd-SHELL NUCLEI IN THE PARTICLE-CORE COUPLING VERSION OF SHELL MODEL

ISOVECTOR EXCITATIONS OF sd-SHELL NUCLEI IN THE PARTICLE-CORE COUPLING VERSION OF SHELL MODEL. N.G. Goncharova Skobelzyn Institute of Nuclear Physics, Moscow State University. 50 YEARS of Multiparticl e Shell Model (MSM). G.E.Brown,M.Bolsterly ,Phys.Rev.Lett.3(1959)472.

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ISOVECTOR EXCITATIONS OF sd-SHELL NUCLEI IN THE PARTICLE-CORE COUPLING VERSION OF SHELL MODEL

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  1. ISOVECTOR EXCITATIONS OF sd-SHELL NUCLEI IN THE PARTICLE-CORE COUPLING VERSION OF SHELL MODEL N.G. Goncharova Skobelzyn Institute of Nuclear Physics, Moscow State University

  2. 50 YEARS of MultiparticleShell Model (MSM) G.E.Brown,M.Bolsterly,Phys.Rev.Lett.3(1959)472

  3. Beyond particle-hole doorway basis • Expanded basis →

  4. Particle Core Coupling Shell Model Form factors of Electroexcitation Connection with direct reaction spectroscopy

  5. Matrix elements of Hamiltonian

  6. Nuclear photo- and electroexcitation 1ħresonances in sd-shell nuclei:E1, M2, E3, M4, E5,M6 Spin currents contributions to MR Orbital currents contributions to MR

  7. Summed squared form factors

  8. 32S(γ,p) Exp:В.Варламов и др ЯФ.т.28 (1978)590 mb E, MeV

  9. Spectroscopy of pickup reactions on 18O and 22Ne 22Ne 18O

  10. 18O(γ,n) • PCC SM -IzvRAN,72(2008)

  11. O-18 (γ,n)/Exp.J.H. Kelleyea, Nucl. Phys.A564,1 (1993)/

  12. σ, mb E, MeV E1 resonances at photopoint in22Ne Exp: V.V.Varlamov, M.E.Stepanov, BRAS Physics 64 (2000) №3

  13. 27Al+γ → 26Al+n 26Al (T=0) 26Al (T=1)

  14. 27Al+γ → 26Al+n Exp: M.N.Thompson et al // Nucl. Phys.1965.V. 64.P.486.

  15. Dynamic deformations in 27Al photodisintegration • 27Al+γ → 26Al+n 27Al+γ → 26Mg+p H. Röpke, P.M.Endt // Nucl. Phys.A632(1998)173.

  16. Spin- and orbital currents interference in E1 1p shell form factors At q~0.5÷0.6 Fm-1 FE1(p3/2-1d5/2) ~0 /HOWF/

  17. Interference of spin- and orbital currents contributions into MR • Exp:E1 in 12C(e,e’) / Mainz,MAMI A,1988/: Calc. PCCSM

  18. E1 in sd-shell nuclei electroexcitations

  19. Nuclear Orbital M2 Current Orbital M2 TWIST Mode: Orbital current has opposite signes in the upper and lower semispheres. The current vanishes at Z=0 (e,e’) excitation ~Spin +orbital(twist) modes (p,p’) excitations –SPIN part only Comparison of (e,e’) and (p,p’) reveals ORBITAL TWIST M2-

  20. ORBITAL (TWIST) M2 MODE in the transitions from sd-shell

  21. M2 in32S q = 0.6 fm-1 F2 105 F2 106 E, MeV Experiment: S-DALINAC 1997(Emax=14 MeV)

  22. Spin and orbital currents in M2 32S g=0.7g free q = 0.6 fm-1 F E, MeV

  23. q-dependence of M2 peaks

  24. M6 stretched states in sd shell • Spin current contributions only:

  25. M6 in sd-shell nuclei : 28Si 2 102 F2 102 q = 1.8 Fm-1 E, MeV S.Yen, T.E.Drake et al., Phys.Lett.B289, 22(1992)

  26. M6 in Ca-40

  27. M6 in sd-shell nuclei : 32S PCCSM, NG,Phys.At.Nucl.(2009)#10 Exp.: Clausen B.L et al , Phys.Rev.C48, 1632(1993).

  28. Summary • The deviation of (A) nucleus from closed shells or subshells reveals in a wide range of energy distribution for ”hole” among the (A-1) nuclei states. In the PCC version of SM these distributions are taken into account in microscopic description of multipole resonances using spectroscopy of pick-up reactions. • The energy spread of final nuclei states is the main origin of the multipole resonances fragmentation in open shell nuclei. Comparison of PCC SM results with experimental data on MR confirms the validity of this approach for a range of momentum transfer from “photopoint” up to q≈2 Fm-1. • The assumption that some very valuable information on MR in excited deformed nucleus is embedded in direct reactions spectroscopy data proved to be right.

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