States of 13C with abnormal radii

Differential cross-sections of the elastic and inelastic 13 C + α scattering were measured at E( α ) = 90 MeV. The root mean-square radii( R rms >) of 13 C nucleus in the states: 8.86 (1/2 − ), 3.09 (1/2 + ) and 9.90 (3/2 − ) MeV were determined by the Modified diffraction model (MDM). The radii of the first two levels are enhanced compared to that of the ground state of 13 C, confirming the suggestion that the 8.86 MeV state is an analogue of the Hoyle state in 12 C and the 3.09 MeV state has a neutron halo. Some indications to the abnormally small size of the 9.90 MeV state were obtained.