Book contents
- Frontmatter
- Contents
- Preface
- 1 Naturally occurring and artificially produced nuclei
- 2 Charge and matter distribution in nuclei
- 3 The semi-empirical mass formula and nuclear stability
- 4 Nuclear fission and the liquid-drop model
- 5 Shell structure and magic numbers
- 6 The nuclear one-particle potential in the spherical case
- 7 The magnetic dipole moment and electric quadrupole moment for nuclei with closed shells ±1 nucleon
- 8 Single-particle orbitals in deformed nuclei
- 9 The shell correction method and the nuclear deformation energy
- 10 The barrier penetration problem – fission and alpha-decay
- 11 Rotational bands – the particle–rotor model
- 12 Fast nuclear rotation – the cranking model
- 13 The nucleon–nucleon two-body interaction
- 14 The pairing interaction
- Solutions to exercises
- References
- Index
13 - The nucleon–nucleon two-body interaction
Published online by Cambridge University Press: 12 January 2010
- Frontmatter
- Contents
- Preface
- 1 Naturally occurring and artificially produced nuclei
- 2 Charge and matter distribution in nuclei
- 3 The semi-empirical mass formula and nuclear stability
- 4 Nuclear fission and the liquid-drop model
- 5 Shell structure and magic numbers
- 6 The nuclear one-particle potential in the spherical case
- 7 The magnetic dipole moment and electric quadrupole moment for nuclei with closed shells ±1 nucleon
- 8 Single-particle orbitals in deformed nuclei
- 9 The shell correction method and the nuclear deformation energy
- 10 The barrier penetration problem – fission and alpha-decay
- 11 Rotational bands – the particle–rotor model
- 12 Fast nuclear rotation – the cranking model
- 13 The nucleon–nucleon two-body interaction
- 14 The pairing interaction
- Solutions to exercises
- References
- Index
Summary
We have already discussed the nucleon one-body potential as the coherent external field exerted on one nucleon due to the presence of all the others. We shall now go on to analyse the basic characteristics of the underlying two-body interaction (the strong interaction).
Knowledge of this interaction rests, in part, on the observation of the properties of very simple nuclear systems. Historically, interest centred very much on the deuteron (consisting of a bound state of a neutron and a proton). Also, simple systems such as the trinucleon systems lend themselves to a direct test of the internucleon interaction.
In part the knowledge – and this is now the overwhelmingly important source – derives from a study of the properties of the scattering of protons against protons and protons against neutrons.
To reproduce the remarkably constant quantity of 8 MeV binding per nucleon encountered all over the periodic table, one has to postulate that nuclear forces have a very short range. We thus conclude as a general gross feature, a nucleon–nucleon interaction (or two-body potential) of the character exhibited in fig. 13.1 in terms of the inter-nucleon distance r.
The range, as roughly defined by fig. 13.1, we associate with the distance b marked in the figure. It is found empirically to be of order b = 1.4 fm. This is exactly the Compton wave length of the pi-meson (pion) or b = ħ/mπc. This in turn is indicative of the fact that at this relatively long range (i.e. in the outer regions of the interaction potential) the important agent, transmitting the interaction between the nucleons, is the pi-meson.
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- Chapter
- Information
- Shapes and Shells in Nuclear Structure , pp. 259 - 289Publisher: Cambridge University PressPrint publication year: 1995