Analyses of low energy π+-12C, 16O elastic scattering data using inverse scattering theory and suggested scaling method

The elastic scattering data for low-energy (T-pi <= 80 MeV) positive pions from carbon-12 and oxygen-16 nuclei has been successfully analyzed by using our local optical potential based on the inverse scattering theory within the framework of the full Klein-Gordon equation. It is found that the same potential parameters used in the pi(-)-C-12, cases are still valid for pi(+)-C-12 with a need to change the three parameters R-0, V-1 and W-3 with the pion's incident kinetic energy T-pi. This is also found to hold in analyzing successfully the measured angular distributions for pi(+)-O-16 in the same energy region. The systematic trends in the changed three free potential parameters R-0, V-1 and W-3 with T-pi are compared to their counterparts for pi(+)-C-12. The different relations obtained for the two cases under consideration, pi(+)-C-12 and pi(+)-O-16 reveals their dependence on the atomic weight of the target nucleus. As such, this suggests the use of a scaling method to obtain the potential parameters for a certain pion-nucleus system, as pi(+)-O-16, from a similar nearby one, as pi(+)-C-12. Further studies are needed to confirm our new findings.