1. Standard model of fundamental particles and interactions
SMU quarknet 2008

2. Standard Model of Particles
What is the standard model and why do we have one?
The standard model is a theory that scientists have been looking for since people have asked ”what’s that made of?”
It consists of three simple principles
All matter is composed of a relatively few types of fundamental particles.
These particles interact with each other in a few specific ways.
Everything that takes place in the universe results from interactions between fundamental particles

3. Evolution of standard models
Ancient Greeks
Four elements
Dalton and Mendeleev
92 elements (aye!!! Too many!!!)
Thomas, Rutherford, and Chadwick
Electron, proton, and neutron ( ah, its simple again)
The discovery of other mysterious particles ruined that idea. Then scientists had to go and predict even more particles (and find them) and the “particle zoo” was created. Not a simple system.

4. Some of the mysterious particles
Antimatter- just like normal matter but with an opposite charge.
Muon- mysterious visitor from outer space
Pion- predicted to “stick” the nucleus together.
Mesons- middle sized particles (more on these later)
Hyperons- particles heavier than protons and neutrons and have a “strangeness” about them.

5. In the late ‘60s two theories were proposed and when combined together made a model that had the few simple particles scientists wanted.
Quantum Electrodynamics (QED)- (simplified) at high energies the electromagnetic force and the weak force are the same, the Electroweak force.
Quantum chromodynamics (QCD)- some fundamental particles have “colors” or “colours” if your English. Its like charge but different.

7. Fermions- the “fundamental particles”, named after Enrico Fermi
Fermions- the “fundamental particles”, named after Enrico Fermi. Every thing seems to be made from a combination of these.
Two types
Leptons- small Greek coins
Quarks- almost spelled “kwork” by there discoverer? Murray Gell-Mann.
There are only four fermions “normally” in our everyday life.
Electrons
Up quarks
Down quarks
Neutrinos

8. Three Generations-the more energy you put in the higher the generation
Three Generations-the more energy you put in the higher the generation. Things also get heavier
E=mc2

9. Non fundamental particles-made of fundamental particles
Hadrons- combinations of quarks

10. Theory of everything Strong Electro-weak Grand unified theory
Four Fundamental Forces
Which is demonstrated to condense into three
Which is theorized to condense to two
Which we hope to condense into one
Strong
Theory of everything
Electro-weak
Grand unified theory
Electro-magnetic
Weak
Gravity

11. Force carriers- forces on the quantum level are interactions between gauge bosons. A force is actually an exchange of these bosons.

12. Properties of the interactions- how it all fits together-

13. How do we know what we know?
Two ways-
Wait for things to fall apart (nuclear decay)
Smash things together and see what comes out (particle accelerators)

14. Problems with the Standard Model
Higgs boson- needed to complete the model by giving mass to particles.
Graviton- force carrier for gravity. Force is so weak that a particle accelerator would need to be galactic in size to achieve the energy levels needed.
Quantum electrodynamics and quantum chromodynamics do not play friendly with general relativity (gravity)