Neutron Charge Distribution (GEn)

The world data set on GEn, including data from two Jefferson Lab experiments, E93-026 (using a polarized deuteron target) and E93-038 (using an unpolarized deuteron target and a recoil polarimeter), and other experiments that have used polarized targets and recoil polarimeters.
Enlarge

The Q2 dependence of the charge form factor of the neutron, GEn, can provide vital information on the origin of charge distribution in the neutron. A precise determination of GEn has challenged physicists for more than 40 years, primarily from the lack of a free neutron target and the fact that the charge form factor is so small.

The application of new techniques and technologies at Jefferson Lab has allowed decisive steps to be made toward rectifying the situation, with two experiments providing a precise measurement of the charge form factor out to large Q2. These unique experiments have put the neutron charge form factor on nearly equal footing with the other nucleon form factors. For the first time, data are available which constrain any modern theory which attempts to describe all four nucleon form factors: the proton electric and magnetic form factors and the neutron electric and magnetic form factors.

References:
H. Zhu et al., Phys. Rev. Lett. 87 (2001) 081801
R. Madey et al., Phys. Rev. Lett. 91 (2003) 122002
G. Warren et al., Phys. Rev. Lett. 92 (2004) 042301
B. Plaster et al., Phys. Rev. C 73 (2006) 025205