Has the Breathing Mode Been Known for Many Years?

Abstract

Calculated spectra are presented for the target ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ for 90-MeV ($e, e^{\prime }$), 120-MeV ($\alpha , {\alpha }^{\prime }$), and 80-MeV ($d, d^{\prime }$), reactions using microscopic form factors based on random-phase-approximation eigenvectors. It is shown that the existence of a monopole excitation at about 14 MeV in addition to the well-known giant dipole resonance is consistent with ($e, e^{\prime }$), ($\alpha , {\alpha }^{\prime }$), and ($d, d^{\prime }$) data.