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Tools of Particle Physics. Kevin Giovanetti James Madison University. Equations of Motion Newton Abstract idea of Natural Motion Introduce interaction F=ma Action = Reaction {essentially energy transfer}. Energy energy conservation. ???. Energy energy conservation. ???. SYMMETRY. a.
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Tools of Particle Physics • Kevin Giovanetti • James Madison University
Equations of Motion Newton Abstract idea of Natural Motion Introduce interaction F=ma Action = Reaction {essentially energy transfer}
Energy energy conservation
??? Energy energy conservation ???
a The Lagrangian L can be calculated at several instants of time t, and a graph of L against t can be drawn. The area under the curve is the action. Any different path between the initial and final positions leads to a larger action than that chosen by nature. Nature chooses the smallest action - this is the Principle of Least Action.
Require Nature to be Rotationally symmetric Equation of motion must be invariant under rotation Energy Conservation Time translation
Add a new symmetry SU(2) Proton same as Neutron Interchange proton with a neutron and nothing changes Throw away the charge
Strange IDEA Rotate by different amounts at different locations Add a force to compensate
Strange IDEA Take my internal SU(2) symmetry and require it to be valid even if I vary the amount as a function of x Add a force to compensate Get WEAK & E&M UNIFIED
Take my internal SU(2) symmetry and require it to be valid even if I vary the amount as a function of x Strange IDEA Add a force to compensate Get WEAK & E&M UNIFIED Interacting fields must have 0 mass
Symmetry Breaking HIGGS
Symmetry Breaking HIGGS Most mass E=mc2 quark masses are few MeV Proton mass is 938 MeV Neglect Dark Matter & Dark Energy
Higgs Mass Point particle mass, charge Space-time ==> separate ingredient but transformations via Lorentz transformations. Standard notions [infinite, continuous] Basic mathematics for some underlying rules [vectors, derivatives…] Basic mechanics Relativezed Newton’s Laws ==>energy, momentum cons… Lagrangian, Hamilton formulations are equivalent Interactions Maxwell’s equations ==> E, B fields Newtonian Gravity
Scintillator Photomultiplier SiPM
TOF E&M showers (high speed ==> Bremstrahlung) Hadronic Showers (neutron Nucleus collision) Ionization track through a low mass ==> gas + wires Pb/scintillator Sample a shower Chernkov radiation