Breathing-mode measurements in Sn isotopes and isospin dependence of nuclear incompressibility

T. Li {\it et al.}[Phys. Rev. C {\bf 81}, 034309 (2010)] have analyzed their measured breathing-mode energies of some tin isotopes in terms of a first-order leptodermous expansion, and find for the symmetry-incompressibility coefficient $K_{\tau}$ the value of -550 $\pm$ 100 MeV. Removing an approximation that they made, we find that the first-order estimate of $K_{\tau}$ shifts to -661 $\pm$ 144 MeV. However, taking into account higher-order terms in the leptodermous expansion shows that the data are compatible with the significantly lower magnitudes indicated by both another experiment and some theoretical estimates.
Comment: 6 pages, 1 figure