  We use the tools of hybrid intranuclear-cascade/nuclear-de-excitation models
to evaluate the sensitivity of several physical observables to the inclusion of
a multifragmentation stage in the de-excitation chain and assess the need for a
multifragmentation model in the quantitative description of p+56Fe and p+136Xe
reactions at 1-GeV incident energy. We seek clear signatures of
multifragmentation by comparing different state-of-the-art de-excitation models
coupled with intranuclear-cascade models and by focusing on discriminating
observables such as correlations and fragment longitudinal-velocity
distributions. None of the considered observables can be unambiguously
interpreted as a multifragmentation footprint. The experimental data are best
described as originating from sequential binary decays. However, no
de-excitation model can reproduce the experimental longitudinal-velocity
distributions from 1-GeV p+136Xe.
