Particle Physics Flashcards
What are the constituents of the atom?
Protons, neutrons and electrons
What are the nucleons?
Protons and neutrons
Where do electrons reside?
They orbit the nucleus in discrete energy shells.
What are the different properties of protons, neutrons and electrons?
What is specific charge?
Charge per unit mass
What is the proton number denoted by?
Z
What is the nucleon number denoted by?
A
What are isotopes?
Atoms with the same number of protons but a different number or neutrons.
What is strong nuclear force?
The force that acts between nucleons to counteract the electrostatic force of repulsion between protons.
What is the range of strong nuclear force?
0 - 0.5 fm: repulsive
0.5 - 3 fm: attractive
>3 fm: no effect
What causes nuclei to be unstable?
Too many protons, neutrons or both causing the strong nuclear force to be too weak to keep them stable and hence causing decay
How do we know that neutrinos exist?
In beta decay, a neutrino must also be emitted alongside the beta particle
What happens in pair production?
A high-energy gamma photon, when in contact with a nucleus, emits two particles in opposite directions - one particle as the antiparticle to the other.
What is y-axis in Feynman diagram?
Time
What are the leptons?
Electrons, muons, tauons and their corresponding neutrinos.
What must be conserved in particle interactions?
1) Baryon number
2) Electron lepton number
3) Muon lepton number
4) Charge
5) Strangeness (only in strong interactions)
6) Energy and momentum
What are the exchange particles and which forces do they correspond to?
1) Gluons - strong nuclear force
2) Virtual photons - electrostatic forces
3) W + / W - bosons - weak nuclear force (interactions where charge is not neutral)
4) Z bosons
What are fermions?
Quarks and leptons
What are the quarks?
- up, down, charm, strange, top, bottom
- antimatter equivalents
What is the most stable quark and why?
- up quark
- higher mass means more unstable
What is the range of electrostatic force?
Infinite
What are the different types of hadrons and what are each of them made of?
1) Baryon - 3 quarks
2) Mesons - 2 quarks (1 quark and 1 antiquark)
What are the types of baryons and what are they made of?
1) Proton - up up down
2) Neutron - up down down
3) Antiproton - antiup antiup antidown
4) Antineutron - antiup antidown antidown
up has charge 2/3
down has charge -1/3
What is an antiparticle?
A particle with the same mass but opposite charge as the corresponding particle.