Nuclei in the Cosmos XII - Satellite Workshop

Single-particle resonant states embedded in the continuum for ${}^{131,133}$Sn, in the vicinity of the neutron capture threshold for ${}^{130,132}$Sn(n,$\gamma$), are calculated by the analytical continuation of the coupling constant (ACCC) approach within the relativistic mean field (RMF) theory framework. Our fully self-consistent RMF calculations using the NL3 effective interaction, predict single-particle bound levels near the Fermi surface, consistent with Nature report for ${}^{133}$Sn and recent measurement for ${}^{131}$Sn. For the first time, the level structure of single-particle resonant states in ${}^{131,133}$Sn up to 3 $\sim$ 4 MeV above the neutron capture threshold are investigated. Our RMF+ACCC+BCS approach determines a level spacing that is too sparse for typical level density formulation used to calculate capture cross section with a Hauser-Feshbach (HF) formalism.