Improved chiral nucleon-nucleon potential up to next-to-next-to-next-to-leading order

TL;DR

This paper develops improved chiral nucleon-nucleon potentials up to next-to-next-to-next-to-leading order, reducing artifacts and enhancing the accuracy of nuclear force modeling without additional regularization.

Contribution

It introduces a coordinate-space regularization method that reduces finite-cutoff artifacts and eliminates the need for spectral function regularization in chiral potentials.

Findings

Reduced finite-cutoff artifacts in nucleon-nucleon potentials.

Potentials constructed without fine-tuning of low-energy constants.

Improved convergence and uncertainty estimation in chiral expansion.

Abstract

We present improved nucleon-nucleon potentials derived in chiral effective field theory up to next-to-next-to-next-to-leading order. We argue that the nonlocal momentum-space regulator employed in the two-nucleon potentials of Refs. [E. Epelbaum, W. Gloeckle, U.-G. Mei{\ss}ner, Nucl. Phys. A747 (2005) 362], [D.R. Entem, R. Machleidt, Phys. Rev. C68 (2003) 041001] is not the most efficient choice, in particular since it affects the long-range part of the interaction. We are able to significantly reduce finite-cutoff artefacts by using an appropriate regularization in coordinate space which maintains the analytic structure of the amplitude. The new potentials do not require the additional spectral function regularization employed in Ref. [E. Epelbaum, W. Gloeckle, U.-G. Mei{\ss}ner, Nucl. Phys. A747 (2005) 362] to cut off the short-range components of the two-pion exchange and make use of the low-energy constants c_i and d_i determined from pion-nucleon scattering without any fine tuning. We discuss in detail the construction of the new potentials and convergence of the chiral expansion for two-nucleon observables. We also introduce a new procedure for estimating the theoretical uncertainty from the truncation of the chiral expansion that replaces previous reliance on cutoff variation.