Key Definitions Flashcards
What is the liquid drop model?
The liquid drop model is described by the semi empirical mass equation. Where nuclei with even number of protons and neutrons are the most strongly bound and magic numbers correspond to shell closures in the nuclear shell model.
How is the binding between protons and neutrons mediated?
mediated by the exchange of pions.
What is Isospin?
Isospin describes the similarity between protons and neutrons, including their independence of the strong interaction on the electric charge of a particle.
What is the phenomenon known as confinement?
The strong interaction allows mediating gluons to interact with each other
Where is alpha decay most commonly found?
In heavy nuclei
Where is beta minus decay more commonly found?
In nuclides with excess neutrons
What does the fermi function depend on?
The fermi function depends on atomic number of the daughter nucleus, and the kinetic energy of the emitted charged particle.
What is the decay rate of beta decay given by?
The interaction strength, the matrix element Mfi and a momentum dependent integral over the Fermi function.
What is an Isobar?
Nuclei with the same A.
What is an Isotone?
Nuclei with the same N but different Z.
What is an Isomer?
Metastable excited state
What is an Isotope?
Nuclei with the same Z different N.
What is the force between a nucleon and how is it mediated?
Strong force by exchange of gluons.
What is the force between two nucleons and how is it mediated?
Nuclear force by exchange of virtual meson.
Describe Electron scattering
Electrons are not subject to strong interaction. They are pointlike particles that can exploit polarisation.
What reveals the size and form factor of nuclei?
Elastic electron scattering
How is the size of a nucleus estimated and what are the challenges involved?
Rutherford’s experiments with alpha-decay showed the size of the nucleus. With challenges due to the modification scattering probability due to a tiny, dense nucleus.
How is the mass of a nucleus determined?
From the molar mass of a substance
What are the Q value conditions?
When Q > 0 it is exothermic and for Q < 0 it is endothermic.
How do we determine the mass of isobars?
From a second-order polynomial obtained from the semi-empirical mass equation and A.
What are the conditions of the pairing term?
For δ = 0 we have odd-A and a single parabola. For even A we have two parabolas separated by 2δ/sqrt(A).
Describe electromagnetic interaction probes.
Using electromagnetic interaction probes probe the charge distribution of the nucleus.
What does Fermi’s golden rule link?
Quantum theory to experimental observation (cross section)
How can the density of a nuclei be described?
Nuclei have near constant density and a diffuse rim.