1. The 2008 Nobel Prize in Physics

2. Symmetries Symmetries often give us a way to characterize how forces interact. Here, a mirror symmetry flips left and right, “Parity” takes (x,y,z) to (-x,-y,-z) A force that looks the same with coordinates reversed would be described as “invariant” under a parity transformation

3. Charge and Parity in Particle Physics

4. Forces arise from force-carrying particles interacting with the matter particles: ee ee ee ee  ee u d WW

5. Interactions It turns out that, for quarks and neutrinos, the Weak force has a “different” interaction axis than ordinary matter:  m1m1 m2m2 Weak axis So, we see the mass states as (m 1, m 2 ), but the weak interaction sees (-m 1 sin  +m 2 cos , m 1 cos  +m 2 sin  ) The weak states are mixtures of the old mass states (m 1, m 2 )

6. Symmetry-Breaking Rotation Matrix for quark states: General Form: This allows an asymmetry between matter and antimatter (CP violation), that has been observed. This is good: the Universe wouldn’t exist without it! Masses are now Complex numbers!