Lattice chiral effective field theory with three-body interactions at next-to-next-to-leading order

TL;DR

This paper advances lattice chiral effective field theory by incorporating three-body interactions at NNLO, computing energies and scattering phases for few-nucleon systems with novel lattice methods.

Contribution

It introduces methods for determining three-body interaction coefficients and applies them to compute energies and phase shifts in few-nucleon systems at NNLO.

Findings

Accurate triton energy calculation

Neutron-deuteron scattering phase shifts obtained

Alpha particle energy computed with auxiliary fields

Abstract

We consider low-energy nucleons at next-to-next-to-leading order in lattice chiral effective field theory. Three-body interactions first appear at this order, and we discuss several methods for determining three-body interaction coefficients on the lattice. We compute the energy of the triton and low-energy neutron-deuteron scattering phase shifts in the spin-doublet and spin-quartet channels using Luescher's finite volume method. In the four-nucleon system we calculate the energy of the alpha particle using auxiliary fields and projection Monte Carlo.