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Y. Tanushi

Publications and source records attributed to Y. Tanushi.

4 recordsLinked to original sources
arXiv1999

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

The spin-averaged electromagnetic polarizabilities of the hyperons $Λ$ 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.

nucl-th↗
arXiv1999

Spin-Polarizabilities of the Nucleon in Chiral Soliton Model with Dispersion Relation

We calculate the spin-polarizabilities of the nucleon by means of dispersion relation, where the pion photoproduction amplitude predicted by chiral soliton model is utilized. We consider the $Nπ$ and $Δπ$ channels in the pion-photoproduction amplitude, and also evaluate the contribution of the anomalous term of the $π^0γγ$ process. In a narrow decay-width limit of the $Δ$ particle the result coincides with that in heavy baryon chiral perturbation theory (HBChPT) except for the interference part of the electric and magnetic amplitudes. A comparison with the multipole analysis is given.

nucl-th↗
arXiv1997

Spin-dependent Polarizability of Nucleon with Dispersion Relation in the Skyrme Model

We calculate the spin-dependent polarizability of the nucleon in the Skyrme model. The result is compared with that of a heavy baryon chiral perturbation theory(HBChPT), and is shown to be the same as that of HBChPT up to the $Δ$-pole terms in the narrow width limit of the $Δ$ state and with the experimental physical constants. The effect of the $Δ+π$ channel is rather small and is numerically quite similar to that of the $Δ$ loop in the HBChPT. The electric and magnetic polarizabilities are recalculated using the transverse photon and a consistent inclusion of the $Δ$ width.

hep-ph↗