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Outline lecture (HL- 3 )

Outline lecture (HL- 3 ). Structure of nuclei NN potential exchange force Terra incognita in nuclear landscape Neutron matter Halo nuclei Hypernuclei Literature: PR 16, 17. scattered. in. nucleon-nucleon scattering.

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Outline lecture (HL- 3 )

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  1. Outline lecture (HL-3) • Structure of nuclei • NN potential • exchange force • Terra incognita in nuclear landscape • Neutron matter • Halo nuclei • Hypernuclei • Literature: PR 16, 17 Kernfysica: quarks, nucleonen en kernen

  2. scattered in nucleon-nucleon scattering positive (negative) phase shift for attractive (repulsive) potential Kernfysica: quarks, nucleonen en kernen

  3. phase shift (degrees) 50 0 -50 energy dependence of NN phase shifts s wave: short range repulsive long range attractive p wave: repulsive Phys. Rev. 182 (1969)1714 Kernfysica: quarks, nucleonen en kernen

  4. NN potential shape and strength attractive singlet/triplet s wave, repulsive p wave scattering attractive non-central Tensor term, and LS (spin-orbit) term repulsive core r < 0.49 fm Hamada, Johnston Nucl. Phys. 34 (1962) 382 Kernfysica: quarks, nucleonen en kernen

  5. general form of NN potential depends on NN separation relative momentum angular momentum must be scalar, P and T invariant, 2N symmetric central spin-spin Tensor spin-orbit Tensor term: non-central force mixes different L-states: 4% 3D1-state in d LS term: induces polarized scattered beams Kernfysica: quarks, nucleonen en kernen

  6. polarized scattering p wave (l=1) scattering: symmetric spin wf. (S=1); VLS < 0 repulsive, scattered left attractive, scattered left parallel spins : scattered left ü polarizati on ý anti - parallel spins : scattered right þ Kernfysica: quarks, nucleonen en kernen

  7. l = 1 l = 0 quark state for NN system short distance repulsion: chromomagnetic spin-spin interaction 6 quarks in s-state (l=0): symmetric spin-isospin wf. minimizing chromomagnetic energy  minimizing parallel quark spins  distorting wave function symmetry: =1/9 =8/9 required excitation energy  strong short range repulsion Kernfysica: quarks, nucleonen en kernen

  8. covalent bonds and meson exchange force energetic favourable spin=0, isospin=0 di-quark direct q exchange suppressed by color restriction virtual meson exchange: Yukawa potential color-neutral (sea-quark) exchange: relativistic form of covalent strong force Kernfysica: quarks, nucleonen en kernen

  9. nuclear equation-of-state in-medium interactions and selfenergies determined in relativistic Dirac-Brückner Hartree-Fock theory from realistic NN potential pure neutron matter is unbound Z=0 -16 MeV Kernfysica: quarks, nucleonen en kernen

  10. terra incognita spherical shell closure for Z>112? 100Sn 48Ni 78Ni nuclei: strongly interacting quantum systems of finite size, balanced by isospin-symmetric strong, -violating Coulomb force Kernfysica: quarks, nucleonen en kernen

  11. single-particlelevels nlj shell gaps and intruder states p: (s1/2)2(p1/2)1 n: (s1/2)2(p3/2)4(p1/2)2 Kernfysica: quarks, nucleonen en kernen

  12. halo nuclei quantum phenomenon: weakly bound valence neutrons in classical forbidden region beyond potential barrier with low l i.e. low centrifugal barrier, single-particle structure and strong pairing correlations 2n-halo region of 11Li as large as 208Pb radius, mixed (p1/2)2 (s1/2)2 configuration multi-nucleon halos: neutron-droplets? N/Z=3 Kernfysica: quarks, nucleonen en kernen

  13. shell quenching at large N/Z 2n-separation energies  shell gap reduced from 6 MeV (100Sn) to 2 MeV (78Ni) • n-potential changes • from WS- to • softer HO-shape •  reduced spin-orbit • splitting • high-l intruder moved back across shell gap Kernfysica: quarks, nucleonen en kernen

  14. creating and detecting hypernuclei p K-  binding energy: - () 0 by choice of kinematics (=0) Kernfysica: quarks, nucleonen en kernen

  15.  spectrum and levels of hypernuclei -levels not restricted by Pauli principle in neutron-like potential (shallower for weaker -N interaction) 11 MeV  • may sit in occupied n-levels n from below the Fermi level Kernfysica: quarks, nucleonen en kernen

  16. binding energy of  in nuclei • in discrete levels V0  30 MeV Kernfysica: quarks, nucleonen en kernen

  17. production of  hypernuclei (S=-2) H dibaryon (uuddss) ?? study of hyperon-hyperon interaction c (-) = 4.91 cm, long-lived enough to be captured Kernfysica: quarks, nucleonen en kernen

  18. Summary lecture (HL-3 ) • Nuclear structure • Potential and phase shifts • NN potential: general form; spin-spin, spin-orbit, tensor part • exchange force: virtual di-quark (meson) exchange • Terra incognita in nuclear landscape • Tasks for exotic-beam facilities • Neutron matter: large N/Z for light nuclei • Halo nuclei observed • Hypernuclei: binding energy and structure Kernfysica: quarks, nucleonen en kernen

  19. structure of nuclei: Fermi gas model number of neutron (N) and proton (Z) states up to Fermi momentum: V(r) r V0=EF+B´ average kinetic energy: Kernfysica: quarks, nucleonen en kernen

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