Particle-vibrator coupling model calculation of partial radiative widths for p3/2 wave neutron resonance on 28Si

A particle-vibrator coupling model was applied to the calculation of partial radiative widths for the 28Si p3/2 wave neutron resonance with large reduced neutron width. The calculation assumed a neutron excitation coupled to one-phonon vibrational states of the 28Si nucleus and neglected the continuum nature of the resonance state wave function in the nuclear external region. The model wave functions were generated from a coupled-channel Schroedinger equation so as to reproduce the observed neutron escape width, neutron binding energies, and spectroscopic factors. Excellent agreement was achieved between the observed and calculated partial radiative widths for the transitions from the 565 keV resonance to the low-lying states of 29Si. As a result, it was confirmed that the core excitation is quite essential to explain the observed partial radiative widths. We emphasize that this resonance can be interpreted as a particle-vibrator doorway state common to the neutron and gamma-ray emission channels, and that a dominant component of the doorway-state wave function belongs to the configuration in which a single quasibound 1d3/2 neutron is coupled to the 3- vibrational state of the 28Si nucleus. (orig.)