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Tools of Particle Physics Kevin Giovanetti James Madison University
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Equations of Motion Newton Abstract idea of Natural Motion Introduce interaction F=ma Action = Reaction {essentially energy transfer}
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Energy energy conservation
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Energy energy conservation ???
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SYMMETRY
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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.action Nature chooses the smallest action - this is the Principle of Least Action.ple of Least Action. a
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Require Nature to be Rotationally symmetric
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Equation of motion must be invariant under rotation Time translation Energy Conservation
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Add a new symmetry SU(2) Proton same as Neutron Interchange proton with a neutron and nothing changes Throw away the charge
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Rotate by different amounts at different locations Strange IDEA Add a force to compensate
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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
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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
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Symmetry Breaking HIGGS
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Symmetry Breaking HIGGS Most mass E=mc 2 quark masses are few MeV Proton mass is 938 MeV Neglect Dark Matter & Dark Energy
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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 Higgs Mass
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Scintillator Photomultiplier SiPM
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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
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