Asymptotic normalization coefficients of resonant and bound states from the phase shifts for $\alpha\alpha$ and $\alpha^{12}\rm C$ scattering
/ Authors
/ Abstract
Recently we have published a paper [Irgaziev, Phys. Rev. C 91, 024002 (2015)PRVCAN0556-281310.1103/PhysRevC.91.024002] 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+α and α+C12 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. A contradiction is found between descriptions of the experimental phase shift data for αα scattering and of the Be resonant energy for 2+ state. Using the EFE method, we also calculate the ANC for the Be 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 α+C12 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 ground 0+ state and for the excited 1− and 2+ levels, which are situated near the threshold of α+C12 channel.
Journal: Physical Review C