Département de Physique Nucléaire

Institut de recherche sur les lois fondamentales de l'Univers

  Introducing

for a given incident energy E, the kinematic for eP elastic scattering gives (see figures 1 and 2)

The maximum is obtained a :

Two useful formulae are

The virtual photon is defined by

Its polarization is given by[&make_named_href('', "#HELENE","[]")]

 
Figure 1: Kinematic for ep scattering versus electron scattering angle. Energy of the scattered electron E, , and photon polarisation  

 
Figure 2: Kinematic for ep scattering versus . , , E' versus and photon polarization versus  

In order to separate the contributions of the different form factors to the cross section or the asymmetry, one needs to work at fixed (i.e. fixed ) and vary the scattering angle using the beam energy E. At fixed , We thus have

 
Figure 3: Kinematic for ep scattering. Energy E versus scattering angle at fixed