Precise determination of the electric and magnetic form factors of the proton

Michael O. Distler (A1 collaboration, Mainz)

The electric and magnetic form factors of the nucleons encode information about the spatial distribution of charge and magnetization in the elementary baryonic systems. They provide benchmarks for the understanding of hadronic systems in terms of QCD, either within a fully non-perturbative treatment in terms of lattice QCD or a perturbative treatment within effective field theory.

In the talk the results of a high precision measurement (arXiv:1007.5076) of the elastic electron proton scattering cross section will be presented. The experiment was performed at the Mainz Microtron (MAMI) 3-spectrometer-facility in the Q² range from 0.004 to 1 (GeV/c)². Employing a direct fit of a selection of different form factor models to the measured cross sections, the electric and magnetic form factors were extracted. The experiment adds a new, internally consistent extensive data set to the available world data. This data has been used to determine the charge radius of the proton.

(Seminarraum II)