TEST OF 3-BODY CONTACT SKYRME FORCES WITH SPIN EXCITATIONS IN DEFORMED-NUCLEI

Experimental data on spin M1 strength distributions in even-even rare- earth nuclei are compared to theoretical results of selfconsistent HFRPA calculations with separable spin-spin residual interactions derive d from the two alternative versions (two-body density-dependent and th ree-body contact terms) of the Skyrme force Sk3. It is shown that the two versions produce quite different spin M1 strength distributions, t hough they generate the same HF mean field. The experimental data favo ur the two-body over the three-body version of the Skyrme interactions Sk1-Sk6.