particle and nuclear structure 1.7

• strong interaction


  only involves hadrons, no change in quark flavour, typically collision between particles
• E-M interaction


  particles must be charged or have charged components, no change in quark flavour, photons are emitted
• weak interactions


  neutral leptons are involved, may be changed in quark flavour
• what numbers should be conserved for interactions

  charge, baryon number, lepton number
• strong force


  experienced by all quarks, range is short
• e-m force


  experienced by all charged particles, range is infinite, also experience by neutral hadrons as composed of quarks
• weak force


  experienced by all leptons, all quarks, range is very short, only significant when e-m and strong don't operate
• gravitational force


  experienced by all matter, range infinite, very weak- negligible except in cases such as planets
• baryons and anti baryons

  all quarks have a baryon number of a third and anti is - a third, baryon number of 1
• hadrons


  made up of 3 quarks, baryon is 3 quarks, anti baryon is 3 anti quarks, meson is 1 quark and anti quark pair
• leptons 


  lepton number always 1
• anti particles


  every particle has equivalent anti-particle which has same properties except opposite charge
• quarks


  hadron number of up quark is 2 thirds, hadron of down quark is minus a third
• leptons


  electron has charge -1 anti neutrino charge 0