Unified description of ⁶Li structure and deuterium-⁴He dynamics with chiral two- and three-nucleon forces

الأصل · EN

Prototype for the study of weakly bound projectiles colliding on stable targets, the scattering of deuterium (d) on ⁴He (α) is an important milestone in the search for a fundamental understanding of low-energy reactions. At the same time, it is also important for its role in the Big-bang nucleosynthesis of ⁶Li and applications in the characterization of deuterium impurities in materials. We present the first unified ab initio study of the ⁶Li ground state and d-⁴He elastic scattering using two- and three-nucleon forces derived within the framework of chiral effective field theory. The six-nucleon bound-state and scattering observables are calculated by means of the no-core shell model with continuum. %and are compared to available experimental data. We analyze the influence of the dynamic polarization of the deuterium and of the chiral three-nucleon force, and examine the role of the continuum degrees of freedom in shaping the low-lying spectrum of ⁶Li. We find that the adopted Hamiltonian correctly predicts the binding energy of ⁶Li, yielding an asymptotic D- to S-state ratio of the ⁶Li wave function in d+α configuration of -0.027 in agreement with the value determined from a phase shift analysis of ⁶Li+⁴He elastic scattering, but overestimates the excitation energy of the first 3+ state by 350 keV. The bulk of the computed differential cross section is in good agreement with data.