Strong-interaction fine structure effects in antiprotonic148Nd

Antiprotonic x ray spectra of146Nd and148Nd have been measured with Ge detectors. Different attenuations of the two fine structure components of the antiprotonic x ray group (n=9 → n=8) due to the E2 nuclear resonance effect were observed in148Nd. Experiment and present theory disagree. We propose to supplement the ¯p-nucleus potential by a spin-orbit term.