  We report a resonant inelastic x-ray scattering study of charge excitations
in the quasi-one-dimensional Mott insulator SrCuO2. We observe a continuum of
low-energy excitations, in which a highly dispersive feature with a large
sinusoidal dispersion (~1.1 eV) resides. We have also measured the optical
conductivity, and studied the dynamic response of the extended Hubbard model
with realistic parameters, using a dynamical density-matrix renormalization
group method. In contrast to earlier work, we do not find a long-lived exciton,
but rather these results suggest that the excitation spectrum comprises a
holon-antiholon continuum together with a broad resonance.
