Particle Physics

Particle Physics

1. Stable and Unstable Nuclei

   • Stable Nuclei
     • The strong nuclear force holds nuclei together through the use of a subatomic particle called a Gluon. This particle travels between the subatomic particles in the nucleus and holds them together. It is an extremly strong force although it only acts over a very small distance.
   • Unstable Nuclei
     • Large Nuclei are more unstable due to their size and will decay to become more stable. This can either be alpha or beta decay Which uses the weak force
       • The weak force isn't as strong as the strong force but it acts over a longer distance. It uses W and Z bosons and causes decay in nuclei
       • Alpha decay is when an alpha particle is ejected from the nucleus. an Alpha particle is 2 neutrons and 2 protons
       • Beta minus decay is when a neutron in the nucleus turns into a proton. This causes an electron or beta particle to be ejected as well as an anti neutrino

2. Particles, Antiparticles and Photons

   • For every particle there is an anti-particle equivalent.
     • Anderson discovered the positron or anti-electron in 1933
       • Beta plus decay was also discovered as a possibility. It is when a proton turns into a neutron causing a positron and neutrino to be produced.

3. Particle interactions

   • Particles interact in many different ways such as combining to make a new product
   • When particles decay they will make use of a transfer particle
     • Gluons for strong force
     • Bosons for weak force
     • Photons for electromagnetic force
     • Gravitons (unproven) for gravity

4. Quarks and antiquarks

   • Quarks are fundamental particles which make up other larger particles
   • 3 quarks make up a baryon such as the proton or neutron
   • 2 quarks can make up a Hadron

5. Applications of Conservation Laws

   • The laws that must be followed for a decay to be possible
     • Mass
     • Charge
     • baryon number
     • Lepton number
     • Strangeness

6. The photoelectric effect

   • When Photons collide with metals electrons are emitted
   • Only occurs on the upper half of the electromagnetic spectrum