Light-Nuclei Spectra from Chiral Dynamics

In recent years local chiral interactions have been derived and implemented in quantum Monte Carlo methods in order to test to what extent the chiral effective field theory framework impacts our knowledge of few- and many-body systems. In this Letter, we present Green’s function Monte Carlo calculations of light nuclei based on the family of local two-body interactions presented by our group in a previous paper in conjunction with chiral three-body interactions fitted to bound- and scattering-state observables in the three-nucleon sector. These interactions include $\mathrm{\Delta }$ intermediate states in their two-pion-exchange components. We obtain predictions for the energy levels and level ordering of nuclei in the mass range $A=4–12$, accurate to $\le 2\%$ of the binding energy, in very satisfactory agreement with experimental data.

Figure 1

Diagrams illustrating schematically the contributions to the chiral $3N$ interaction. Nucleons, $\mathrm{\Delta }$’s, and pions are denoted by solid, thick-solid, and dashed lines, respectively. The circle in panel (b) represents the vertex involving the LECs $c_1$, $c_3$, and $c_4$ in ${\mathcal{L}}_{\pi N}^{(2)}$.

Figure 2

The energy spectra of $A=4–12$ nuclei obtained with the $\mathrm{NV}2+3\text{−}\mathrm{Ia}$ chiral interactions are compared to experimental data [54]. Also shown are results obtained with the phenomenological $\mathrm{AV}18+\mathrm{IL}7$ interactions [1].