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. nucleonnucleon scattering.
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Kernfysica: quarks, nucleonen en kernen
in
nucleonnucleon scatteringpositive (negative) phase shift for attractive (repulsive) potential
Kernfysica: quarks, nucleonen en kernen
50
0
50
energy dependence of NN phase shiftss wave: short range repulsive
long range attractive
p wave: repulsive
Phys. Rev. 182 (1969)1714
Kernfysica: quarks, nucleonen en kernen
attractive singlet/triplet s wave,
repulsive p wave scattering
attractive
noncentral Tensor term,
and LS (spinorbit) term
repulsive core r < 0.49 fm
Hamada, Johnston
Nucl. Phys. 34 (1962) 382
Kernfysica: quarks, nucleonen en kernen
depends on NN separation
relative momentum
angular momentum
must be scalar, P and T invariant, 2N symmetric
central
spinspin
Tensor
spinorbit
Tensor term: noncentral force mixes different Lstates: 4% 3D1state in d
LS term: induces polarized scattered beams
Kernfysica: quarks, nucleonen en kernen
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
l = 1
l = 0
quark state for NN systemshort distance repulsion: chromomagnetic spinspin interaction
6 quarks in sstate (l=0): symmetric spinisospin 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
energetic favourable
spin=0, isospin=0 diquark
direct q exchange suppressed
by color restriction
virtual meson
exchange:
Yukawa
potential
colorneutral
(seaquark) exchange:
relativistic form of
covalent strong force
Kernfysica: quarks, nucleonen en kernen
inmedium interactions and selfenergies determined in relativistic
DiracBrückner HartreeFock theory from realistic NN potential
pure neutron matter
is unbound
Z=0
16 MeV
Kernfysica: quarks, nucleonen en kernen
spherical
shell closure
for Z>112?
100Sn
48Ni
78Ni
nuclei: strongly interacting quantum systems of finite size,
balanced by isospinsymmetric strong, violating Coulomb force
Kernfysica: quarks, nucleonen en kernen
quantum phenomenon: weakly bound valence neutrons
in classical forbidden region beyond potential barrier
with low l i.e. low centrifugal barrier,
singleparticle structure and strong pairing correlations
2nhalo region of
11Li as large as
208Pb radius,
mixed
(p1/2)2 (s1/2)2
configuration
multinucleon
halos:
neutrondroplets?
N/Z=3
Kernfysica: quarks, nucleonen en kernen
2nseparation
energies shell gap
reduced from 6 MeV
(100Sn) to 2 MeV (78Ni)
moved back
across shell gap
Kernfysica: quarks, nucleonen en kernen
p
K
binding energy:

()
0 by choice of kinematics
(=0)
Kernfysica: quarks, nucleonen en kernen
levels not restricted by Pauli principle
in neutronlike potential (shallower for weaker N interaction)
11 MeV
occupied nlevels
n from below
the Fermi level
Kernfysica: quarks, nucleonen en kernen
V0 30 MeV
Kernfysica: quarks, nucleonen en kernen
H dibaryon (uuddss) ??
study of
hyperonhyperon interaction
c () = 4.91 cm,
longlived enough
to be captured
Kernfysica: quarks, nucleonen en kernen
Kernfysica: quarks, nucleonen en kernen
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