Quarks and Leptons

Quarks and Leptons

1. 2.1 The Particle zoo

   • Space invaders
     • Cosmic particle + Earth atmosphere = short live particles
     • Muon
       • Heavy electron
       • Symbol: µ
       • Negatively charged
     • Pion
       • Symbol: Pi
       • can be pi+, pi0 or pi-
       • Pi Meson
     • Kaon
       • K Meson
       • can be K+, K0 or K-
       • Symbol: K
   • A strange puzzle
     • Kaon is a strange one
     • K decays into pi mesons, muons and antineutrinos and antimuons and neutinos
     • Charged pi mesons decay into muons and antineutrinos, or antimuons and neutrinos
     • Pi0 forms high energy photons
     • Muons and antimuons decay into electrons and antineutinos or positrons and neutrinos
     • Only decay through weak force

2. 2.2 Particle sorting

   • Classifying particles and anti particles
     • Particle
       • Charge
         • Antiparticle
           • Charge
             • Rest energy MeV
               • Interaction
     • Proton p
       • +1
         • antiproton
           • -1
             • 938
               • Strong,weak,electro
     • Neutron n
       • 0
         • antineutron
           • 0
             • 939
               • Strong, weak
     • electron e-
       • -1
         • positron e
           • +1
             • 0.511
               • Weak, electro
     • neutrino v
       • 0
         • antineutrino
           • 0
             • 0
               • weak
     • muon µ
       • -1
         • antimuon µ+
           • +1
             • 106
               • Weak, electro
     • Meson pi pi+, pi0, pi-
       • +1,0,-1
         • pi-,pi0,pi+
           • -1, 0, +1
             • 140, 135, 140
               • Strong, electro
     • K Meson K+, K0, K-
       • -1,0,+1
         • -1, 0, +1
           • 494, 498, 494
             • Strong, electro
     • Hadrons are particles and antiparticles that can interact through the strong interaction
       • Protons, neutrons, pi mesons, kmesons
         • Hadrons interact through the strong and electro if charged. Apart from proton (stable), hadron decay through weak
     • Leptons are particles and antiparticles that do not interact through the strong interaction
       • Electron, muons, neutrinos
         • Leptons interact through the weak and electro if charged
   • Energy Matters
     • The rest energy of the products=total energy before - the kinetic energy of the products
   • Baryons and Mesons
     • Baryons are protons and all other Hadrons. That decay into protons either directly or indirectly
     • Mesons are hadrons that do not include protons in their decay products. K and pi are not baryons
     • Matter and anti matter
       • Hadrons
         • Baryons
         • Mesons
       • Leptons

3. 2.3 Leptons at work

   • Lepton collisions
     • They interact to produce Hadrons
     • Example: High energy electron + positron = baryons, antibaryons and mesons
   • Neutrino types
     • Muon neutrino
     • electron neutrino
     • Muon decay
     • • Absorber
     • ------------------->
       • electrons, positrons, neutrinos and antineutrinos from muon decay
     • ------------------->
       • neutrinos and antineutrinos only
     • • Target
       • ------------------->
         • Muons and antimuons and neutrinos and antineutrinos that did not react
       • Muons and anti muons on target
   • Lepton rules
     • 1. In an interaction between a lepton and a hadron, a neutrino or antineutrino can change into or form a corresponding charged lepton
       • Ve + n --> p + e-
         • Lepton number: +1 --> +1
       • Ve + n --> anti p + e+
         • Lepton number: +1 --> -1
     • 2. In muon decay, the muon changes into a muon neutrino. In addition, an electron and an electron antineutrino are created to conserve charge
       • µ- --> e- + anti Ve + Vµ
         • Lepton number: +1 --> +1 -1 +1
       • µ- --> e- + anti Ve + anti Vµ
         • Lepton number: +1 --> +1 -1 -1
     • A weak puzzle

4. 2.4 Quarks and antiquarks

5. 2.5 Conservation rules