Particle Interactions Concept of exchange particles to explain

Particle Interactions Concept of exchange particles to explain forces between elementary particles The electromagnetic force; virtual photons as the exchange particle. The weak interaction limited β-, β+ decay, electron capture and electron-proton collisions; W+ and W- as the exchange particles. Simple Feynman diagrams to represent the above reactions or interactions in terms of particles going in and out and exchange particles.

1 • Concept of exchange particles to explain forces between elementary particles.

2 Force Exchange Particle electromagnetic Photon (γ) weak interaction W+, W- Strong interaction Gluon (g)

3 The electromagnetic Interaction Possible areas of questioning a) Repulsion/Attraction of charged particles b) Annihilation c) Pair Creation

Simple Repulsion between like charged electrons. The particle of exchange is the photon ee- γ ee-

Electromagnetic Interaction Annihilation and Pair Creation THESE PROCESSES ARE EXACT OPPOSITES OF ONE ANOTHER

Weak Interaction The weak interaction limited to β-, β+ decay, electron capture and electron-proton collisions; W+ and W- as the exchange particles.

β- decay Decay at the Quark Level udd uud

β+ decay Decay at the Quark Level e+ νe d W+ u uud udd

Electron Capture And Electron Proton Collisions At The Quark ν Level d e W- uud e u udd