Inelastic scattering of 50 MeV/nucleon Ca-40 on Ca-40 was measured in
coincidence with protons in order to investigate the excitation and de
cay of highly excited states in Ca-40. The proton decay pattern corres
ponding to an excitation region around 34 MeV shows the characteristic
behavior expected of the direct decay of a two-phonon state. Thus, by
using this novel method, the presence of a double-phonon state built
with isoscalar giant resonances in Ca-40 is demonstrated.