Kernfysica: quarks, nucleonen en kernen Outline lecture (HL-3) HL-3 May 2004 Structure of nuclei NN potential exchange force Terra incognita in nuclear landscape Neutron matter Halo nuclei Hypernuclei Literature: PR 16, 17 HL-3 May 2005 Kernfysica: quarks, nucleonen en kernen Kernfysica: quarks, nukleonen en kernen

nucleon-nucleon scattering positive (negative) phase shift for attractive (repulsive) potential in scattered HL-3 May 2005 Kernfysica: quarks, nucleonen en kernen

energy dependence of NN phase shifts phase shift (degrees) 50 -50 s wave: short range repulsive long range attractive p wave: repulsive Phys. Rev. 182 (1969)1714 HL-3 May 2005 Kernfysica: quarks, nucleonen en kernen

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 HL-3 May 2005 Kernfysica: quarks, nucleonen en kernen

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 HL-3 May 2005 Kernfysica: quarks, nucleonen en kernen

Kernfysica: quarks, nucleonen en kernen 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 ý polarizati on anti - parallel spins : scattered right þ HL-3 May 2005 Kernfysica: quarks, nucleonen en kernen

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: l = 0 l = 1  =1/9 =8/9 required excitation energy  strong short range repulsion HL-3 May 2005 Kernfysica: quarks, nucleonen en kernen

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 HL-3 May 2005 Kernfysica: quarks, nucleonen en kernen

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 HL-3 May 2005 Kernfysica: quarks, nucleonen en kernen

Kernfysica: quarks, nucleonen en kernen 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 HL-3 May 2005 Kernfysica: quarks, nucleonen en kernen

Kernfysica: quarks, nucleonen en kernen 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 HL-3 May 2005 Kernfysica: quarks, nucleonen en kernen

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 HL-3 May 2005 Kernfysica: quarks, nucleonen en kernen

creating and detecting hypernuclei K-  binding energy: - () 0 by choice of kinematics (=0) HL-3 May 2005 Kernfysica: quarks, nucleonen en kernen

 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 HL-3 May 2005 Kernfysica: quarks, nucleonen en kernen

binding energy of  in nuclei in discrete levels V0  30 MeV HL-3 May 2005 Kernfysica: quarks, nucleonen en kernen

production of  hypernuclei (S=-2) H dibaryon (uuddss) ?? study of hyperon-hyperon interaction c (-) = 4.91 cm, long-lived enough to be captured HL-3 May 2005 Kernfysica: quarks, nucleonen en kernen

Kernfysica: quarks, nucleonen en kernen HL-3 May 2004 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 HL-3 May 2005 Kernfysica: quarks, nucleonen en kernen Kernfysica: quarks, nukleonen en kernen

structure of nuclei: Fermi gas model number of neutron (N) and proton (Z) states up to Fermi momentum: V(r) r average kinetic energy: V0=EF+B´ HL-3 May 2005 Kernfysica: quarks, nucleonen en kernen