  Polarized inelastic light scattering experiments on Cu_(1-x)Zn_xGeO_3 (0<= x
<= 0.045) single crystals show for x<>0 a new distinct mode at nearly half the
energy of the singlet response below the spin-Peierls transition. The
temperature, magnetic field, polarization, and doping dependencies of this mode
are similar to those of the singlet bound state. The data are interpreted in
terms of a spinon-assisted light scattering process. Position and form of the
peak provide strong evidence for the presence of dopant-bound spinons in
Cu_(1-x)Zn_xGeO_3.
