particless

• leptons that have no charge are called

  neutrinos
• the electromagnetic force is carried by the photon
• neutrinos can only interact with the weak field.
• the strong force is carried by gluons
• Which particle group interacts with every field?

  Quarks
• These two leptons are identical to the electron just much heavier:

  Muons and taus
• The fermion group is made up of quarks and leptons
• All muons/taus decay into electrons within the first fraction of a second via the weak force
• When muons/taus decay they release photons and neutrinos
• The natural process of cosmic rays hitting the atmosphere produces muons
• Natural processes with high enough energy produce muons and taus
• Neutrinos are very hard to detect why?

  they interact with matter very very rarely
• which leptons have very small masses

  neutrinos
• the sum of all 3 neutrino masses is less than 0.3 electron volts
• because they have mass, neutrinos can oscillate between lepton flavours
• a hadron is a composite particle
• type of radiation decay in the nucleus of some radioctive atoms


  Beta minus decay
• a neutron is a composite particle
• a neutron is a type of hadron called a baryon
• no experiment has ever produced a quark in isolation
• quarks are free to move, but if they move too far apart they are brought back together by the strong force.
• quarks are confined to bound states of 2 or 3
• bosons are particles that carry energy and forces throughout the universe
• A feynman diagram is a space time diagram that describes how particles move and interact
• A virtual particle is a particle that exists for too short a time to be observable
• A virtual particle can exist for a finite amount of time with the energy being “borrowed” from its uncertainty