2. What are we made of ?

6. Neutrinos

7. Building a Particle Collider The ring is 27km round and on average 100m underground CERN – LEP, LHC

8. We need particles… The hydrogen source for protons at the LHC…

9. We need to accelerate them… Van de Graff Generator + Plasma Ball

10. LHC RF cavity

11. We need to control them… Cathode ray tube + magnets

12. Accelerator Physics Electron positron annihilation to a photon allows us to convert their energy to look for all the particles that make up nature E = m c 2

13. The Large Hadron Collider collides the nuclei of atoms with 10 times higher energy than has previously been achieved (14 TeV) 1232, 35 ton, superconducting dipole magnets accelerate ions and focus them into bunches for collision 36,000 tons of coolant below 2K! LHC

14. Proton-Proton collisions (hydrogen atom nuclei) 100 billion protons per bunch 20 collisions per crossing 1 crossing every 25ns 600 million collisions per second 14 TeV centre of mass energy To store all collision data would involve storing 10 Petabytes of data a year ie a 20km high stack of CDs… more than can be made

15. Detection… Cloud Chamber

16. Calorimeters… Crystal, glass, liquid Acts as absorber and scintillator Light detected by photodetector E.g. PbWO 4 vertex detectors look for inflight decays of particles…

20. What have we found?

25. Why do otherwise identical particles have different masses? There must be a new force that interacts differently with the muon and electron… its quanta are the higgs boson… more in the final lecture…