1 / 18

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.

susanna-rufus
Download Presentation

Outline lecture (HL- 3 )

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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. 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

  12. 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

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

  14.  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

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

  16. 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

  17. 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

  18. 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

More Related