We analyze cross sections for Quasi-Elastic inclusive scattering of electrons
on nuclei and show that the observed isolated peaks for relatively low Q2
are unique for the lightest targets. Focusing in particular on D and 4He, we
investigate in two ways to what measure the above peaks can be allocated to
nucleon-elastic processes. We first compute approximate upper limits for the
nucleon-inelastic background in the Quasi-Elastic region due to inclusive
Δ excitation, and find those to be small. Far more precise is a
semi-phenomenological approach, where the dominance of nucleon-elastic
processes is translated into a set of stringent requirements. We show that
those are very well fulfilled for recent D data, and to a somewhat lesser
extent for older D and 4He data. With knowledge of GE,Mp​ and
information on GEn​, we then extract GMn​ and find agreement with values
obtained by alternative methods. We discuss the sensitivity of the extraction
method and mention future applications.Comment: 21 pages, 9 figures, revtex4, revised version, Phys. Rev. C, in pres