Résumé
We quantitatively study the effects, beyond the SVZ-expansion, due to instanton and tachyonic gluon mass, to the scalar isoscalar two-point functions supporting the fact that the QCD spectral sum do not favour the $\bar uu+\bar dd$ interpretation of the broad and low mass ?(0.6). Then, we emphasize that a measurement of the Ds semileptonic decays into ?? can reveal in a model-independent way its eventual gluon component ?B. The analysis also implies that one expects an observation of the $K\bar K$ final states from the ?B which may compete (if phase space allowed) with the one from a low mass $\bar ss$ state assumed in the literature to be the SU(3) partner of the observed u(0.6) if the latter is a $\bar uu+\bar dd$ state.