  We explain quantitatively why resonant Raman scattering spectroscopy, an
extensively used experimental tool in studying elementary electronic
excitations in doped low dimensional semiconductor nanostructures, always
produces an observable peak at the so-called "single particle" excitation
although the standard theory predicts that there should be no such single
particle peak in the Raman spectra. We have thus resolved an experimental
puzzle which dates back more than twenty-five years.
