Bonn 2010 – wissenschaftliches Programm
HK 4.1: Gruppenbericht
Montag, 15. März 2010, 16:30–17:00, HG III
The electric form factor of the neutron at Q2=1.5 (GeV/c)2 measured at MAMI — •Björn Sören Schlimme — Institut für Kernphysik, Universität Mainz, J.-J.-Becher-Weg 45, D-55128 Mainz
A measurement of the ratio Gen/Gmn at a four momentum transfer squared Q2=1.5 (GeV/c)2 has been carried out at the Mainz Microtron in 2008 in order to extract the electric Sachs form factor of the neutron (Gen) with the magnetic form factor (Gmn) as input.
MAMI-C provided a 1.5 GeV polarized electron beam impinging on a polarized 3He gas target for the study of the reaction 3He→(e→,e′n)pp. The scattered electrons were detected with a standard magnetic spectrometer of the A1 collaboration and a nucleon detector consisting of an array of plastic scintillators inside a heavy lead shield was installed to detect the recoil neutrons in coincidence. Exploiting beam helicity asymmetries for different target polarization orientations, Gen/Gmn can be extracted with comparatively small systematic uncertainties.
The measurement method and the experimental setup will be illustrated, the performance of the polarized 3He target during the beam time will be shown and the status of the analysis will be presented.