YAD-004 · The atomic nucleus Sample material

Nucleon-nucleon scattering at low energies

Neutron–proton and nucleon–nucleon scattering at low energies: partial waves, scattering length and effective range, triplet and singlet states, pp and nn scattering, isospin invariance and the theory of nuclear forces.

Estimated time: 3 h 3 activities

Learning objective

Understand why only s-wave scattering matters at low energies.
Master the relation between scattering length and cross section.
Learn to infer the spin dependence of nuclear forces from the np cross section.
Assess isospin invariance by comparing pp, nn and np scattering lengths.

Expected outcomes

Can compute the wave number k and kR for a given energy and decide which partial waves contribute.
Can calculate the low-energy np cross section from the triplet and singlet scattering lengths.
Can find the recoil-proton energy as a function of angle in elastic np scattering.
Can explain the main ideas of the modern theory of nuclear forces.

Interactive modelNeutron–proton scattering

Activities

Lecture
Lecture · 1 h 20 min · required
Nucleon scattering at low energies. Isospin invariance. The nature of nuclear forces. Theory of nuclear forces
Practice · 1 h 20 min · required
Final test
Test · 20 min · required · pass ≥ 70%

Completion conditions

  • Lecture
  • Nucleon scattering at low energies. Isospin invariance. The nature of nuclear forces. Theory of nuclear forces
  • Final test — at least 70%