1. WHAT’S IN AN ATOM?

2. MATTER Atom ~10 -10 mNucleus ~10 -15 mQuarks <10 -18 m

3. MATTER Atom ~10 -10 mNucleus ~10 -15 mQuarks <10 -18 m Fundamental Particles:  Electron  Quarks: Up (u) & Down (d) Force Carriers:  Photon: carries EM force  Gluon: binds quarks in nuclei

4. 3 Generations of Matter:  Heavier  Same properties and interactions.

5. 3 Generations of Matter:  Heavier  Same properties and interactions.  Felt only by Quarks  Force increases with distance – binds quarks into proton/neutrons

6. 3 Generations of Matter:  Heavier  Same properties and interactions.  Affects only Quarks  Force increases with distance – binds quarks into proton/neutrons  Affects all particles  Responsible for nuclear/radioactive decay  Massive bosons?

7. 3 Generations of Matter:  Heavier  Same properties and interactions.  Felt only by Quarks  Force increases with distance – binds quarks into proton/neutrons  Affects all particles  Responsible for nuclear/radioactive decay  Affects all charged particles  Causes lightning, magnetic fields

8. 3 Generations of Matter:  Heavier  Same properties and interactions.  Felt only by Quarks  Force increases with distance – binds quarks into proton/neutrons  Affects all particles  Responsible for nuclear/radioactive decay  Massive bosons?  Affects all charged particles  Causes lightning, magnetic fields  Explains Chemistry???  Tiny effects on individual particles  Not included in the Standard Model

9. THE HIGGS BOSON One particle predicted by the Standard Model has yet to be discovered: The HIGGS particle

10. THE HIGGS BOSON One particle predicted by the Standard Model has yet to be discovered: The HIGGS particle  Needed to explain how the other particles gain masses  LEP at CERN excluded masses below 114 GeV  Must have a mass less than 1000 GeV for the model to be correct  Major motivation for building the LHC at CERN

11. THE HIGGS BOSON One particle predicted by the Standard Model has yet to be discovered: The HIGGS particle  Needed to explain how the other particles gain masses  LEP at CERN excluded masses below 114 GeV  Must have a mass less than 1000 GeV for the model to be correct  Major motivation for building the LHC at CERN WILL DISCOVER THE HIGGS PARTICLE OR, IF THE MODEL IS WRONG, SOMETHING ELSE !

12. UNANSWERED QUESTIONS  Why 3 generations?  Why 4 forces – can they be unified?  Many parameters, masses, etc. must be put in by hand  Difficult to keep the Higgs mass small  Dark Matter – what is it?  Gravity – how do we include it?

13. UNANSWERED QUESTIONS  Why 3 generations?  Why 4 forces – can they be unified?  Many parameters, masses, etc. must be put in by hand  Difficult to keep the Higgs mass small  Dark Matter – what is it?  Gravity – how do we include it? Theorists have hypothesised many models to explain these, eg.  Supersymmetry – predicts a heavier partner for each particle in the SM  Extra dimensions – possibility of producing minute black holes that decay in the detector after 10 -26 s

14. Backups

15. The Standard Model LightestHeaviest 3 Generations of Particles