On ab initio calculations and Asymptotic Normalization Coefficients in ⁶Li

Calculations of the A=6 system that employ the No-Core Shell Model with Continuum (NCSMC) have produced ⁶Li wave functions and α-deuteron phase shifts for a variety of interactions derived from Chiral Effective Field Theory (ChiEFT) [1]. Both the Asymptotic Normalization Coefficients (ANCs) of the s-wave component of these wave functions and the amount by which ⁶Li is bound compared to the α-deuteron threshold vary across the different NCSMC calculations. I will first show that each ANC is consistent with the corresponding low-energy s-wave α-deuteron phase shifts, i.e., can be derived from those phase shifts by extrapolation to the bound state pole. The extarpolation is, however, sensitive to the functional form used for the inverse amplitude and the range of positive energies over which the NCSMC phase shfits are reproduced. Nevertheless, the predicted ANCs are strongly correlated with the ab initio predictions for the deuteron separation energy of ⁶Li. This correlation is explained by the interior part of the α-deuteron s-wave radial wave function's insensitivity to details of the NCSMC calculation.

[1] C. Hebborn, G. Hupin, K. Kravvaris, S. Quaglioni, P.Navrátil and P. Gysbers, Phys. Rev. Lett. 129, 042503 (2022).