Eur. Phys. J. Special Topics 198, 257-267 (2011)
https://doi.org/10.1140/epjst/e2011-01493-0

Review

Experimental studies of few-body systems at MAMI

Institute for Nuclear Physics, University of Mainz, J.J. Becher-Weg 45, 55099 Mainz, Germany

^a e-mail: distler@uni-mainz.de

Received: 8 July 2011
Revised: 21 July 2011
Published online: 23 September 2011

Abstract

Few-body experiments at the Mainz Microtron were focused on a number of selected topics. Double-polarization experiments to determine the neutron electric form factor G_en have been performed using both deuterium and polarized helium-3 targets. The structure of ³He has been studied in the reactions ³H e⃗ e(e⃗e,e′n) and ³H e⃗ e(e⃗e,e′p) with large (transversal) missing momenta and in quasi-elastic electron scattering. Electromagnetically induced two-nucleon knockout has been investigated in order to study the role of correlated nucleon-nucleon motion in the nucleus. Measurements of the (e,e′pn) reaction on ³He and ¹⁶O were performed for the first time. A triple-polarization experiment of type ³H e⃗ e(e⃗e,e′e⃗p⃗)d has been performed, where, in addition, the spin of the knocked out proton is analyzed. This measurement provides information on the spin-dependent momentum distribution of proton-deuteron clusters in the ³He nucleus. Hence, by tagging the outgoing deuteron spin-polarized ³He might also serve as an effective polarized proton target for electron scattering experiments. Moreover, in inclusive ^3,4He(e,e′) measurements at low momentum transfer, the effect of 3-body-forces has been studied.