  We show that the string-breaking distance can be read from meson-production
data, by employing a previously derived expression for the production
amplitude. Accordingly, we find that the radii of 0.67, 0.34 and 0.20 fm for
the creation of non-strange q-qbar pairs obtained in the
Resonance-Spectrum-Expansion model, for light-quark, c-cbar, and b-bbar
environments, respectively, are in perfect agreement with S-wave di-pion
production data, upon employing an ansatz with no additional free parameters.
