Neutron-proton scattering with lattice chiral effective field theory at next-to-next-to-next-to-leading order

TL;DR

This paper introduces a new lattice formulation of chiral effective field theory for neutron-proton scattering, improving accuracy and simplifying the fitting process, enabling more precise ab initio nuclear calculations.

Contribution

A novel lattice formulation of chiral effective field theory interactions with simplified spin channel decomposition and improved phase shift accuracy at N3LO.

Findings

Lattice phase shifts are more accurate than previous studies.

Results obtained for multiple lattice spacings up to N3LO.

Provides a pathway for systematic ab initio nuclear calculations.

Abstract

We present a new lattice formulation of chiral effective field theory interactions with a simpler decomposition into spin channels. With these interactions the process of fitting to the empirical scattering phase shifts is simplified, and the resulting lattice phase shifts are more accurate than in previous studies. We present results for the neutron-proton system up to next-to-next-to-next-to-leading order for lattice spacings of $1.97$, $1.64$, $1.32$, and $0.99~{\rm fm}$. Our results provide a pathway to $\textit{ab initio}$ lattice calculations of nuclear structure, reactions, and thermodynamics with accurate and systematic control over the chiral nucleon-nucleon force.