Unit 2 - Particles and radiation

Unit 2 - Particles and radiation

1. Constituents of the atom

   • Charge & Masses
   • AXZ Notation
   • DEFINITION OF AN ISOTOPE
     • Each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons.

2. Stable and unstable nuclei

   • STRONG NUCLEAR FORCE
     • The strong nuclear force; its role in keeping the nucleus stable; short-range attraction up to approximately 3 fm, very-short range repulsion closer than approximately 0.5 fm.
   • ALPHA AND BETA DECAY
     • Unstable nuclei; alpha and beta decay
     • The existence of the neutrino was hypothesised to account for conservation of energy in beta decay

3. Particle interactions

   • FUNDAMENTAL INTERACTIONS
     • Four fundamental interactions: gravity, electromagnetic, weak nuclear, strong nuclear. (The strong nuclear force may be referred to as the strong interaction.)
     • Exchange Particles
     • The weak interaction is limited to β− and β+ decay, electron capture and electron–proton collisions; W+ and W− as the exchange particles.

4. Particles, antiparticles and photons

   • For every type of particle, there is a corresponding antiparticle.
   • Photon model of electromagnetic radiation
   • Planck's constant
   • Annihilation and pair production
   • Particle Table

5. Classification of particles

   • Muons and tau particles decay into electrons.
   • Conservation of strangeness in strong interactions, but not guaranteed in weak interactions
     • Strangeness can change by 0, +1 or -1 in weak interactions.
   • The pion is the exchange particle of the strong nuclear force.
   • Kaon+ Decay
     • The decay of a kaon ( K+ ) into three pions (2 π+ , 1 π− ) is a process that involves both weak and strong interactions.
     • Weak interactions : The strange antiquark ( s ) of the kaon transmutes into an up antiquark ( u ) by the emission of a W+ boson; the W+ boson subsequently decays into a down antiquark ( d ) and an up quark ( u )
     • Strong interactions : An up quark ( u ) emits a gluon ( g ) which decays into a down quark ( d ) and a down antiquark ( d ).
   • All baryons eventually decay into a proton (The only stable baryon).
   • CONSERVATION LAWS
     • Baryon No, Lepton No & Charge must always be conserved!

6. Quarks & Antiquarks

   • Neutron Decay
   • Quark Properties

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