(2.1) - Particles and Radiation Flashcards
(2.1.1) What do each letter stand for
AZX Notation:
A: Nucleon Number
Z: Proton Number
X: Chemical Symbol
How to calculate specific charge of nuclei
- SC = Total Charge / Total Mass
- Total charge = number of protons X 1.6 X 10^-19
- Total Mass = (number of protons X rest mass of proton) + (number of neutrons X rest mass of neutron)
How to calculate specific charge of ion
- SC = Total charge / Total Mass
- Total charge = 0 - Number of electrons gained
- Total Mass = (number of protons X rest mass of proton) + (number of neutrons X rest mass of neutron)
Isotope definition
- Atoms of same element with same number of protons and electrons but different number of neutrons
(2.1.2)
What is the Strong Nuclear Force (SNF)
- The force keeping protons and neutrons together
Repulsion range in SNF
0 - 0.5 fm
Attraction range in SNF
0.5 - 3 fm
Alpha decay
- Nucleus emmiting 2 protons and 2 neutrons
Beta - Decay
n -> p + β- + ̅νe
Beta + Decay
p -> n + β+ + νe
Annihilation
When a particle meets its corresponding antiparticle they are both destroyed and their mass is converted into energy in the form of two gamma-ray photons
Explain how the existance of the neutrino was hypothesised
- In B- decay, electrons had a range of energies, not one fixed energy
- This means there was missing energy, so it was hypothesised that there was another particle carrying the remained energy
How does a particle and antiparticle’s masses, charge and rest energy (MeV) compare?
- Same masses and rest energy, but opposite charge
What is a photon
- Massless quantum of EM energy
Pair Production
When a photon interacts with a nucleus or atom and the energy of the photon is used to create a particle–antiparticle pair
Four fundamental interactions:
- Strong
- Weak
- Gravitational
- Electromagnetic
Exchange Particle for SNF
Pion
Exchange particle for Weak interaction
W boson (W+ or W-)
Exchange particle for Electromagnetic interaction
Virtual photon
The weak interaction occurs in —
- β decay
- Electron capture
- Electron-proton collision
Hadrons are subject to the … interaction
Strong
The two classes of hadrons:
- baryons (proton, neutron) and antibaryons
(antiproton and antineutron) - mesons (pion, kaon) and antimesons (antipions and antikaon)
All quantum numbers:
- Baryon
- Lepton
- Strange
- Charge
What is the only stable baryon
proton
What particles are subject to conservation
- Lepton
- Charge
- Baryon
What do kaons decay into
Pions
What are the different kind of Leptons
- Electron
- Muon
- Neutrino
What does a muon decay into
Electron
How are strange particles produced and how do they decay
- Produced in strong interaction
- Decays in weak interaction
Explain conservation of strangeness in all interactions
- Strong, EM and Gravitational : fully conserved
- Weak : Can change by -1, 0, and 1
Why do particle physics relies on the collaborative efforts of large teams of scientists and engineers
- High cost
- Validate new knowledge
- Ensures accuracy across different teams
Properties of quarks and antiquarks
- Charge
- Baryon number
- Strange number
Combination of quarks required for Proton and Neutrons (Baryons)
- Proton: UUD
- Neutron: UDD
Combination of quarks required for Pions
π:
* + = udˉ
* - = duˉ
* ⁰ = uuˉ and 𝑑𝑑ˉ
Combination of quarks required for Kaons
K:
* + = 𝑢𝑠ˉ
* - = 𝑠𝑢ˉ
* ⁰ = 𝑑𝑠ˉ
* K̅⁰ = sdˉ
3 flavours of quarks
- Up
- Down
- Strange
When is strange number conserved
Every interaction except weak in a range of -1, 0 or 1
- Types of Leptons
- Define them
- Muon, a heavier electron
- Electron
- Neutrino, a nearly mass less particle
Types of mesons
- Pion (SNF exhange particle)
- Kaon (Strange particle, decays into pions)
Quark character change in b- and b+ decay
b- neutron: neutron (udd) to proton (uud)
b+ is opposite
In which interactions are quantities conserved
All except weak, where strangeness is not conserved
