Significance of chiral three-nucleon force contact terms for understanding of elastic nucleon-deuteron scattering

TL;DR

This study highlights the significance of chiral three-nucleon force contact terms in accurately modeling elastic nucleon-deuteron scattering, demonstrating improved predictions across various energies by fitting contact term parameters.

Contribution

It introduces the application of N$^4$LO$^+$ chiral potentials with all subleading N$^4$LO 3NF contact terms to better describe Nd scattering data.

Findings

Enhanced agreement with experimental data across multiple energies.

Neglecting N$^3$LO contributions still yields significant improvements.

Fitted contact terms effectively improve theoretical predictions.

Abstract

We investigate the importance of the three-nucleon (3N) force contact terms in elastic nucleon-deuteron (Nd) scattering by applying the N$^4$LO$^+$ chiral semi-local momentum space (SMS) regularized nucleon-nucleon (NN) chiral potential supplemented by N$^2$LO and all subleading N$^4$LO three-nucleon force (3NF) contact terms. Strength parameters of the contact terms were obtained by least squares fitting of theoretical predictions to cross section and analyzing powers data at three energies of the impinging nucleon. Although the N$^3$LO contributions to the 3N force were completely neglected, the results calculated with the contact terms multiplied by the fitted strength parameters yield an improved description of the elastic Nd scattering observables in a wide range of incoming nucleon energies below the pion production threshold.