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-. 10 lectures. The Standard Model of Particle Physics and Beyond. H. Fritzsch. classical physics : a physical system is given by the functions of the coordinates and of the associated momenta –.
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- 10 lectures The Standard Model of Particle Physics and Beyond H. Fritzsch
classicalphysics:a physicalsystemisgivenbythefunctionsofthecoordinatesandoftheassociatedmomenta –
quantumphysics:coordinatesandmomentaareHermiteanoperators in theHilbert spaceofstates
1927: Schrödinger equation for the wave function Erwin Schrödinger
Oscillator classical
externalsymmetries:Poincare group conservationlaws: energy momentum angular momentum
General Relativity:noenergyconservationnomomentumconservationnoconservationof angularmomentum
internalsymmetries:IsospinSU(3)Color symmetryElectroweakgaugesymmetryGrand Unification: SO(10)Supersymmetry
internalsymmetriesbrokenbyinteraction: isospinbrokenbyquarkmasses: SU(3)brokenby SSB: electroweaksymmetryunbroken: colorsymmetry
symmetrygroups n finite or infinite
examples of groups: integer numbers: 3 + 5=8, 3 + 0=3, 5 + (-5) = 0 real numbers: 3.20 x 2.70=8.64, 3.20 x 1 = 3.20 3.20 x 0.3125 = 1
Niels Abel Norway 19th century
A symmetryisa transformationof thedynamical variables, whichleavethe action invariant.
Classicalmechanics: translationsof spaceand time – ( energy, momentum ) rotationsofspace ( angular momentum )
Special Relativity => Poincare group: translationsof 4 space - time coordinates + Lorentz transformations
Henri Poincare late19th century
Symmetry in quantum physics ( E. Wigner, 1930 … ) U: unitary operator
Eugene Wigner Nobel prize 1964
Poincare group P:- time translations -- spacetranslations -- rotationsofspace -- „rotation“ betweentime andspace -
e.g. rotationsofspace: - - SO(3)< P
symmetry U The operator U commutes with the Hamiltonoperator H: If U acts on a wave function with a specific energy, the new wave function must have the same energy ( degenerate energy levels ).
discretesymmetries P ~ paritysymmetry CP - symmetry CPT - symmetry
P: exactsymmetry in the strong andelectromagneticinteractions
theoryofparityviolation:1956: T. D. Lee andC.N.Yangexperiment: Chien-Shiung Wu( Columbia university )
Lee Yang Wu