Total reaction cross sections from elastic α-nucleus scattering angular distributions around the Coulomb barrier

Compete text of publication follows. The total reaction cross section σreac is a valuable measure for the prediction of α-induced reaction cross sections within the statistical model and for the comparison of scattering of tightly bound projectiles to weakly bound and exotic projectiles. Here we provide the total reaction cross sections σreac derived from our previously published angular distributions of α-elastic scattering on 89Y, 92Mo, 112,124Sn, and 144Sm at energies around the Coulomb barrier. The measured angular distributions cover a broad angular range and thus allow the determination of σreac with small uncertainties of about 3%. The results are listed in Table 1. The data of the tightly bound α projectile are compared to reaction cross sections induced by weakly bound projectiles (6,7,8Li) and the exotic projectile 6He with a neutron halo. A systematic behavior of the so-called reduced cross sections σred versus the reduced energy Ered (as defined in [5]) is found for all nuclei under study (see Figure 1). The understanding of the energy dependence of σreac at low energies is the essential ingredient for the prediction of α-induced reaction cross sections at energies far below the Coulomb barrier where the Gamow window for astrophysical reaction rates is located. The aim of the ongoing studies is to find a consistent α-nucleus potential which is able to describe elastic α-scattering and α-induced reaction cross sections simultaneously.