Analog states of 140La levels

Abstract

Analog states in 140Ce have been studied through elastic and inelastic proton scattering on 139La in the energy range E p = 9–12 MeV. We have shown that the 14 first excited states of 140La can be described by the two configurations [ ( g 7 2 ) p ⊗ ( f 7 2 ) n ] and [ ( d 5 2 ) p ⊗ ( f 7 2 ) n ] according to the assumption of Kern et al. The elastic scattering results are in complete agreement with the 139La(d, p) ones. The study of the inelastic scattering to the 166 keV excited state of 139 La( d 5 2 level) , which gives a direct and sensitive test of the [ ( d 5 2 ) p ⊗ ( f 7 2 ) n ] components, has confirmed that only these two configurations are important and that the relative intensities of the two configurations deduced from (d, p) experiments are correct. On the other hand, the two sets of theoretical wave functions which exist are not able to reproduce experimental results. We are able to confirm that the proton peak observed at E p = 10.3 MeV in the 140Ce(e, e'p) 139La reaction by Shoda et al. corresponds to the analog of the 1 − state at 466 keV in 140La.