Elastic and Inelastic Scattering of Polarized Protons from Lead-206 and Lead-208 Near Isobaric Analog Resonances

摘要

Excitation functions have been measured for elastic scattering of polarized protons from exp 206 Pb and exp 208 Pb, and for inelastic scattering to collective states in exp 206 Pb (2 exp + , 0.8033 MeV; 3 exp - , 2.647 MeV) and exp 208 Pb (3 exp - , 2.6145 MeV). Both differential cross sections and analyzing powers were measured at theta/sub lab/ = 120 exp 0 , 135 exp 0 , 150 exp 0 , and 165 exp 0 , for E/sub p/ = 14.25 to 18 MeV. Fits to the excitation-function data were obtained using scattering amplitudes consisting of sums of resonant and non-resonant parts. The resonances are the isobaric analogs (IARs) of 7 low-lying states in exp 209 Pb and 35 in exp 207 Pb. The fits to the elastic-scattering data are excellent; for the inelastic scattering the fit is very good for the 2 exp + state but only fair for the 3 exp - states. For each IAR, the energy, the total width, and the partial width and mixing phase in each channel were obtained. Also, new spin assignments were made for a number of parent states in exp 207 Pb. The theory of Bund and Blair was used to find the spectroscopic amplitudes, which provide information on the wave functions for the parent states in exp 207 Pb and exp 209 Pb and for the 3 exp - states in exp 206 Pb and exp 208 Pb. These spectroscopic amplitudes were then checked for internal consistency and compared with the results of other experiments and with theoretical predictions. (ERA citation 08:032746)