Proton excitation of1+states inPb208and a lower limit on the strength of the isoscalar spin-flip part of the effective nucleon-nucleon interaction

Excitation of $1^{+}$ states in ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ has been studied by 201 MeV proton inelastic scattering. Strength assigned to $1^{+}$ isovector states is found between 6.0 and 8.2 MeV excitation energy and compared with theoretical predictions. From the cross section of the recently discovered $1^{+}$ ‘‘isoscalar’’ state at 5.846 MeV, a lower limit is extracted for the volume integral of the total equivalent isoscalar spin-flip part of the nucleon-nucleon interaction.