  In order to discuss the spatial extention of the second 0+ state of 12C
(Hoyle state), we analyze the inelastic form factor of electron scattering to
the Hoyle state, which our 3 alpha condensate wave function reproduces very
well like previous 3 alpha RGM/GCM models. The analysis is made by varying the
size of the Hoyle state artificially. As a result, we find that only the
maximum value of the form factor sensitively depends on its size, while the
positions of maximum and minimum are almost unchanged. This size dependence is
found to come from a characteristic feature of the transition density from the
ground state to the Hoyle state. We further show the theoretical predictions of
the inelastic form factor to the second 2+ state of 12C, which was recently
observed above the Hoyle state, and of the inelastic form factor to the
calculated third 0+ state of 16O, which was conjectured to correspond to the 4
alpha condensed state in previous theoretical work by the present authors.
