Modifications of the tensor and spin-orbit interactions and the stretched states in 208Pb

We have reanalyzed the (e,e') and (p,p') data at 318 MeV on the stretched, 121,2- and 14-, states of 208Pb using the ideas of G. Brown and co-workers on the reduction of meson and nucleon masses in the nuclear medium. The reaction calculations are compared with new, large basis random-phase-approximation calculations using a residual interaction, also modified, in a consistent way. The resulting interaction, based on the one boson exchange (π+ρ) model, has reduced tensor and enhanced spin-orbit strengths. Agreement between electron and proton quenching factors is found for effective masses, m*/m congruent 0.79--0.86. The reduction or enhancement factors for the modified interaction are in qualitative agreement with those found in other analyses