Effective Field Theories of Loosely Bound Nuclei

Nuclei with up to $\boldsymbol{A=6}$ nucleons with artificial neural network wave functions

“…The binding energies and charge radii of 2 H, 3 H, 3 He, 4 He, 6 He, and 6 Li obtained with the VMC-ANN and HH methods are listed in Table 1. For nuclei with A ≥ 3, we separately show the results obtained with the two-body force alone (NN ) and with the full LO Hamiltonian of Eq.…”

“…Similarly to the A = 3 case, the VMC-ANN method yields a groundstate energy of 4 He that is ∼ 0.2 above the HH value, whether or not the 3N force is included in the Hamiltonian. However, the repulsive features of the 3N potential are essential to bring the predicted binding energies and charge radii closer to their experimental values.…”

“…The active degrees of freedom at soft scale are hadrons whose interactions are constrained by the symmetries of QCD. Effective potentials and currents are then derived from the most general EFT-Lagrangian, and can be employed to make predictions for nuclear observables in a systematic expansion in Q/M [4]. To describe processes characterized by Q ∼ m π , the best suited approach is chiral-EFT which exploits the (approximate) chiral symmetry of QCD to derive consistent nuclear potentials and currents to estimate and reduce their uncertainties [5,6].…”

“…For distances larger than 1/m π , Q is smaller than both m π and M , so that pions can be integrated out and the nuclear interactions reduce to delta functions and their derivatives [7]. This pionless-EFT is particularly useful when describing systems characterized by distances much larger than the two-nucleon scattering lengths-that is, the two-nucleon scattering amplitude at zero energy [4].…”

“…We solve the Schrödinger equation for the pionless-EFT Hamiltonian of Ref. [34] and compute the binding energies and charge radii of 2 H, 3 H, 3 He, 4 He, 6 He, 6 Li and compare our results with experimental data. The paper is organized as follows.…”