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Light Front Calculations of Nucleon Form Factors - shapes of the proton G A Miller, UW

Light Front Calculations of Nucleon Form Factors - shapes of the proton G A Miller, UW. Experimental progress JLAB Model : relativistic quarks, π cloud, symmetry-aided phenomenology Electromagnetic form factors Shapes of proton , spin of proton Connect with lattice QCD. Definitions.

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Light Front Calculations of Nucleon Form Factors - shapes of the proton G A Miller, UW

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  1. Light Front Calculations of Nucleon Form Factors - shapes of the protonG A Miller, UW • Experimental progress JLAB • Model: relativistic quarks, π cloud, symmetry-aided phenomenology • Electromagnetic form factors • Shapes of proton, spin of proton • Connect with latticeQCD

  2. Definitions

  3. Expectations- Pre Jlab Jlab QF2 /F1 GE/GM GE/GM QF2/F1 Q2 Q2

  4. Implement Relativity

  5. ImpulseApproximation

  6. Wave function

  7. 1995 Frank, Jennings, Miller

  8. Ratio of Pauli to Dirac Form Factors 1995

  9. Relativistic Explanation

  10. Neutron Electric Form Factor

  11. Ratio of Pauli to Dirac Form Factors 2003

  12. Two More Form Factors Needed

  13. Model exists • Lower components OAM • Shape of proton • Spin dependent densities SDD non-rel • Relativistic SDD H atom • Proton

  14. Shapes of the proton

  15. Spin density operator: d(r-rp) s . n PRB65, 144429 Canted ferromagnetic structure of UNiGe high magnetic fields • Neutron magnetic scattering • Neutron, B, crystal

  16. LFCBM and LATTICE FORM FACTORS • H. H. Matevosyan, GAM, AW Thomas • Lattice results described using LFCBM with parameters taken as analytic functions of lattice quark mass • Extrapolate back to physical regime • Form factors look like data • First attempt to relate lattice QCD with form factors that depend on Q2

  17. Reproduce Lattice QCDSF data

  18. Extrapolate to physical, predict

  19. Summary • Phenomenological model –three quark plus pion cloud- of nucleon respects Lorentz invariance and chiral symmetry • Describes form factor data pretty well • Has some connection with lattice/fundamental theory

  20. Extras follow

  21. High Q2

  22. How proton holds together • pQCD Feynman Non perturbative∞ gluon exch

  23. Compton scattering same modelRelativistic Massive Quarks

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