Effect of the N3LO three-nucleon contact interaction on p-d scattering observables

TL;DR

This paper investigates how the N3LO three-nucleon contact interaction influences proton-deuteron scattering observables, demonstrating that low-energy constants can be fitted to experimental data within a hybrid theoretical framework.

Contribution

It introduces a new parametrization of the N3LO three-nucleon contact interaction and shows its compatibility with experimental polarization data in p-d scattering.

Findings

The LECs can accurately fit polarization observables.

The N3LO three-nucleon interaction is of the expected magnitude.

The approach combines chiral EFT with phenomenological potentials.

Abstract

A unitary transformation allows to remove redundant terms in the two-nucleon (2N) contact interaction at the fourth order (N3LO) in the low-energy expansion of Chiral Effective Field Theory. In so doing a three-nucleon (3N) interaction is generated. We express its short-range component in terms of five combinations of low-energy constants (LECs) parametrizing the N3LO 2N contact Lagrangian. Within a hybrid approach, in which this interaction is considered in conjunction with the phenomenological AV18 2N potential, we show that the involved LECs can be used to fit very accurate data on polarization observables of low-energy $p-d$ scattering, in particular the $A_y$ asymmetry. The resulting interaction is of the right order of magnitude for a N3LO contribution.