Candidate toroidal electric dipole mode in the spherical nucleus ⁵⁸Ni

Dipole toroidal modes appear in many fields of physics. In nuclei, such a mode was predicted more than 50 years ago, but clear experimental evidence was lacking so far. Using a combination of high-resolution inelastic scattering experiments with photons, electrons, and protons, we identify for the first time candidates for toroidal dipole excitations in the nucleus ⁵⁸Ni and demonstrate that transverse electron scattering form factors represent a relevant experimental observable to prove their nature.