Mr Adrian Weber (Institut für Kernphysik, Johannes-Gutenberg-Universität Mainz)
The proton is a basic constituent of matter, but its fundamental properties like the radius are, in spite of all effort, still not understood properly. The measurements of the radius via interaction with electrons or muons yield significantly different results, leading to the so called proton radius puzzle. To bring new insight into the observed discrepancy a new electron scattering experiment at Mainz Microtron has been performed using a measuring technique based on initial state radiation. The aim was to determine the charge form factor of the proton with percent precision at Q^2 as low as 3*10^(-4)(GeV/c)^2 , and obtaining a new value of the proton charge radius. The poster will offer a brief introduction to the radius problem as well as the underlying theory and overview of the experiment. The present status of the analysis and preliminary results will also be shown.