One-loop calculations of hyperon polarizabilities under the large n_c consistency condition

The spin-averaged electromagnetic polarizabilities of the hyperons Δ and Σ are calculated within the one-loop approximation by use of the dispersion theory. The photon and meson couplings to hyperons are determined so as to satisfy the large N_c consistency condition. It is shown that in order for the large N_c consistency condition to hold, exotic hyperon states such as Σ** with I=2 and J=3/2 are required in the calculation of the magnetic polarizability of the Σ state. * Electronic address: tanushi@nuc-th.phys.nagoya-u.ac.jp † Electronic address: saito@nuc-th.phys.nagoya-u.ac.jp.