Internal and external radiative widths in the combined R-matrix and potential model formalism

TL;DR

This paper combines the R-matrix and potential models to calculate radiative widths of nuclear resonances, highlighting the interference of internal and external contributions and their dependence on asymptotic normalization coefficients.

Contribution

It introduces a method to compute internal radiative widths using a potential model within the R-matrix framework, linking external widths to ANC and resonance widths.

Findings

External radiative width amplitude is model independent and determined by ANC.

Internal radiative width amplitude can be calculated using a single particle potential model.

Results show good agreement with experimental data.

Abstract

Using the $R$-matrix approach we calculate the radiative width for a resonance decaying to a bound state through electric dipole, $E1$, transitions. The total radiative width is determined by the interference of the nuclear internal and external radiative width amplitudes. For a given channel radius the external radiative width amplitude is model independent and is determined by the asymptotic normalization coefficient (ANC) of the bound state to which the resonance decays. It also depends on the partial resonance width. To calculate the internal radiative width amplitude we show that a single particle potential model is appropriate. We compare our results with a few experimental data.