nuclear physicshagino/lectures/notes1.pdfcontents nuclei: aggregate of nucleons (protons and...
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Nuclear Physics
Nuclear Theory Group,Tohoku UniversityKouichi Hagino
原子核理論特論
東北大学原子核理論研究室萩野浩一
ContentsNuclei: aggregate of nucleons (protons and neutrons)
Nuclear Many-Body Problems
Liquid drop modelSingle-particle motion and Shell structureHartree-Fock approximationBruckner TheoryPairing correlations and Superfluid NucleiAngular momentum and number projectionsRandom Phase ApproximationGenerator Coordinate Method (GCM)Time-dependent Hartree-Fock MethodNuclear Reactions
P. Ring and P. Schuck, “The Nuclear Many-Body Ploblem” A. Bohr and B.R. Mottelson, “Nuclear Structure” Vol. 1 and 2 G.E. Brown, “Unified Theory of Nuclear Models and Forces” D.J. Rowe, “Nuclear Collective Motion”
J. Lilley, “Nuclear Physics” R.F. Casten, “Nuclear Structure from a Simple Perspective” S.G. Nilsson and I. Ragnarsson, “Shapes and Shells in Nuclear Structure”
市村宗武、坂田文彦、松柳研一 「原子核の理論」 (岩波講座・現代の物理学) 高田健次郎、池田清美 「原子核構造論」 (朝倉物理学大系)
References
NuclearPhysics
Nucleus as a quantum many body system
charge mass (MeV) spinProton +e 938.256 ½+Neutron 0 939.550 ½+
Basic ingredients:
(note) n p + e- + ν (10.4 min)
Basic Properties of Nuclei
1 fm = 10-13 cm
Density Distribution
Density Distribution High energy electron scattering
Born approximation:
(Fourier transform of the density)
Form factor
e-
Fermi distribution
(fm-3)(fm)
(fm)
Saturationproperty
Momentum Distribution
Fermi gas approximation
kx
ky
kz
(fm-1)
Fermi energy: (MeV)
(note: spin-isospin degeneracy)kF
Nuclear Mass
B(binding energy)
1. B(N,Z)/A ~ 8.5 MeV (A > 12) Short range nuclear force
Long vs short range interaction
Long range force:
Short range force: saturation
1. B(N,Z)/A ~ 8.5 MeV (A > 12) Short range nuclear force2. Effect of Coulomb force for heavy nuclei
Nuclear Chart
Stable nuclei:
1. B(N,Z)/A ~ -8.5 MeV (A > 12) Short range nuclear force2. Effect of Coulomb force for heavy nuclei3. Fusion for light nuclei4. Fission for heavy nuclei
(Bethe-Weizacker formula: Liquid-drop model)
Volume energy:
Surface energy:
A nucleon near the surface interacts with fewer nucleons.
Semi-empirical mass formula
Coulomb energy:
for a uniformly charged sphere
Symmetry energy:
Potential energy
a nucleon interacting with nuclear matter:
Kinetic energy
Pauli exclusion principle
β-stability line
Stable nuclei (beta-stability line)
Z < A/2
Nuclear Chart
Stable nuclei:
Nuclear Fission
ab
Quantumtunneling
Collective Vibrations
ab
In general,
Quantization: Harmonic Vibrations
(note) moment of inertia incompressible and irrotational flow
λ=2: Quadrupole vibration λ=3: Octupole vibration
0+
2+
0+ 2+4+
0.558 MeV
1.133 MeV1.208 MeV1.282 MeV
114Cd
Double phonon states
Microscopic descriptionRandom phase approximation (RPA)[later in this lecture]