Measurements ofGEn/GMnfrom theH2

R. Madey¹,

Semenov Ay²,

S. Taylor³

et al.

Abstract

We report new measurements of the ratio of the electric form factor to the magnetic form factor of the neutron, G n E /G n M , obtained via recoil polarimetry from the quasielastic 2 H( e, e ′ n) 1 H reaction at Q 2 values of 0.45, 1.13, and 1.45 (GeV/c) 2 with relative statistical uncertainties of 7.6 and 8.4% at the two higher Q 2 points, which were not reached previously via polarization measurements. Scale and systematic uncertainties are small.

Role of mesons in the electromagnetic form factors of the nucleon

“…In that model only the polarization data of Refs. [52,53] were fitted, but not the more recent low-Q 2 BLAST data [54] nor the preliminary higher-Q 2 JLab data [55]. Nevertheless, the 2005 fit agrees very well with the BLAST results and with the preliminary data (not shown).…”

“…As seen in [26] and the Galster et al [27] parametrization with the fitted data (Madey et al [52] and Warren et al [53]; see the end of Sec. II) and recent results from BLAST (Geis et al [54]).…”

Electromagnetic form factors of nucleons with QCD constraints: Systematic study of space- and time-like regions

“…[19]- [41] and the aforementioned recent experimental data, G n M , for the space-like momentum and |G Let us remark on the experiments for the time-like momentum [8,32,34], where the form factors |G p | and |G n | are determined by using the formula for the cross section σ 0 for the processes e +ē → N +N or N +N → e +ē, which is given as…”

“…We find that G p E = 0 at Q 2 = 6.60 (GeV/c) 2 for case I and Q 2 = 6.12 (GeV/c) 2 for case II. The form factor for the time-like momentum, |G|, is given for the proton in [20], Anklin et al [21], Kubon et al [28], Madey et al [41], Xu et al [29], Anderson et al [6], and Lachniet et al [7].…”

“…The solid curve is the result for case I and the dashed one for case II. Data points are taken from Meyerhoff et al[22], Rohe et al[30], Herberg et al[24], Zhu et al[31], Passchier et al[25], Ostrick et al[26], and Madey et al[41].…”