Core polarization and quenching in stretched spin states: Case study of the 9^{-} E_{x}=3.522 MeV state in^{116}Sn

The role of core polarization and of the quenching of the leading shell model configuration in stretched spin states is investigated in a case study of the 9- state at 3.522 MeV in 116Sn. With data on five independent observables available, this is the best documented example of a natural parity stretched (yrast) state. The observables are the electron scattering longitudinal and transverse form factors, the proton-scattering cross section and asymmetry, and the proton-stripping cross section on 115In. By introducing a fully microscopic description of the core polarization, it is possible to account quantitatively for all five observables using an effective nucleon-nucleon interaction based on the free t matrix for the proton scattering and the free values for the coupling constants for electron scattering. A short discussion on the 5- Ex=9.70 MeV state in 28Si and the 12+ Ex=6.026 MeV state in 208Pb is given. Quenching factors for the leading shell model components are found to be similar in magnitude as for unnatural parity states