Pion scattering to 8- stretched states in 60Ni

Using the Energetic Pion Channel and Spectrometer (EPICS) at the Los Alamos Meson Physics Facility (LAMPF), differential cross sections for pion scattering were measured for ten previously known Jπ = 8- stretched states in 60Ni. A possible new pure isoscalar stretched state was also found. The data were taken near the Δ3,3-resonance using 162 MeV incident pions and scattering angles of 65 degree, 80 degree, and 90 degree for π+ and 65 degree and 80 degree for π-. For 60Ni the isoscalar (ΔT = 0) strength was found to be much smaller than the isovector (Δ T = 1) strength, as has been found previously in other nuclei, and the isovector strength was found to be only 25% of that expected from a simple sum rule. The isoscalar and isovector amplitudes of each stretched transition were found by comparing the pion scattering cross sections with previous electron scattering data. The analysis of the 60Ni data found that the use of Woods-Saxon (WS) wave functions in the theoretical calculations gave much better agreement with data than the use of the usual harmonic oscillator (HO) wave functions. This analysis using WS wave functions was extended to five other nuclei (12C, 14C, 16O, 28Si, and 54FE) on which both pion scattering and electron scattering have been done. A significant improvement is arriving at a normalization factor close to unity was found when WS wave functions were consistently used for analyzing both pion and electron inelastic scattering data. This is the first time that a consistent analysis in several nuclei has been done using WS wave functions