Refractive alpha-nucleus scattering: a probe for the incompressibility of cold nuclear matter

Refractive α-nucleus scattering observed at intermediate energies is of great help in determining the α-nucleus potential at small distances, where the overlap density is large. A systematic folding analysis of the elastic α+12C, 40Ca and 90Zr scattering data at Elab = 59.1–172.5 MeV has been performed using effective density dependent NN interactions based on the G-matrix elements of the Reid- and Paris NN potentials. The new interactions consistently reproduce the saturation properties of cold nuclear matter and generate, at the same time, different values of the nuclear incompressibility K. With the existing refractive scattering patterns, it is possible to conclude from our folding analysis that a nuclear incompressibility K ⋍ 220 ± 50 MeV is the most realistic one.