Asymptotic normalization coefficients of resonant and bound states from the phase shifts for alpha alpha and alpha C-12 scattering

作者：Orlov Yu V^*; Irgaziev B F; Nikitina L I

来源：Physical Review C, 2016, 93(1): 014612.

DOI：10.1103/PhysRevC.93.014612

Recently we have published a paper [Irgaziev, Phys. Rev. C 91, 024002 (2015)] where the S-matrix pole method (SMP), which is only valid for resonances, has been developed to derive an explicit expression for the asymptotic normalization coefficient (ANC) and is applied to the low-energy resonant states of nucleon + alpha and alpha + C-12 systems. The SMP results are compared with the effective-range expansion method (EFE) results. In the present paper the SMP and EFE plus the Pade approximation are applied to study the excited 2(+) resonant states of Be-8. A contradiction is found between descriptions of the experimental phase shift data for alpha alpha scattering and of the Be-8 resonant energy for 2(+) state. Using the EFE method, we also calculate the ANC for the Be-8 ground 0(+) state with a very small width. This ANC agrees well with the value calculated using the known analytical expression for narrow resonances. In addition, for the alpha + C-12 states 1(-) and 3(-) the SMP results are compared with the Pade approximation results. We find that the Pade approximation improves a resonance width description compared with the EFE results. The EFE method is also used to calculate the ANCs for the bound O-16 ground 0(+) state and for the excited 1(-) and 2(+) levels, which are situated near the threshold of alpha + C-12 channel.

• 出版日期2016-1-15