FROM EXPERIMENTAL MONOPOLE CROSS-SECTIONS TO NUCLEAR INCOMPRESSIBILITIES

In this letter we test carefully the procedure used to extract strength functions from experimental data. This test is performed on a set of pseudo-data generated from HF and RPA results for monopole resonances in Ca-40, Ni-60, Zr-90 and Pb-208. We show how the scaling approximation used in the experimental analysis may induce systematic errors. We demonstrate, however, that whereas the discrepancy on the high energy component (4h-omegaBAR) can be large. the distortion in the giant monopole resonance region (2h-omegaBAR) is of the order of (10-30)% only. Moreover, we observe that when ratios of moments are considered, the errors partially compensate one another. From this we conclude that the systematic errors on the form factors have little influence on the extracted scaling energy from which nuclear incompressibilities are deduced.