Electromagnetic structure of the deuteron. Experimental determination of the charge form functions. Calculation of the exchange currents with a light cone formalism

The nucleus with a small number of nucleons provide simple systems for the study of the nuclear structure. Made of a proton and a neutron, the deuteron is the unique bound state with two nucleons. Its electromagnetic structure is described by three form factors: charge monopole G_C, charge quadrupole G_Q, and magnetic dipole G_M. Their full determination requires the measurements of the cross-section and the tensor polarization observable. During the t₂₀ experiment performed at Jefferson Laboratory (USA), we measured the tensor polarization, t₂₀, at the largest possible momentum transfer. It was a double scattering experiment which covered a large range of momentum transfers from 4.1 to 6.7 fm^-1, and in which the recoil deuterons performed a second scattering in the polarimeter (POLDER) to analyze their polarization. The structure function A(Q) was also measured. The combination of this measure with the polarization results allowed the separation of the two form factors G_C and G_Q. The experimental determination of the elastic electromagnetic form factors of the deuteron represents a strong test to different theoretical models. The results are thus compared to different existing approaches. Finally, relativistic calculations are made in the framework of the light front dynamics in view of an improved interpretation of our experiment by including the recoil contributions and ρπγ current to the ed elastic scattering. (author)