Enhancement of deltaful two-pion exchange nuclear forces

TL;DR

This paper investigates the impact of delta isobar degrees of freedom on two-pion exchange nuclear forces, revealing significant differences based on regularization methods and suggesting adjustments in power counting for better understanding.

Contribution

It provides a comparative analysis of regularization schemes in deltaful two-pion exchange potentials and proposes adjustments to power counting to improve nuclear force modeling.

Findings

Spectral function regularization shows large cutoff dependence.

Deltaful two-pion exchange potentials have unexpectedly large numerical factors.

Adjustments in power counting are discussed to enhance theoretical consistency.

Abstract

The role of the delta isobar degrees of freedom in nucleon-nucleon scattering is revisited. We attempt to understand why the dimensionally regularized two-pion exchanges with the explicit delta isobar is much stronger than the ones with spectral function regularization. When the cutoff value of spectral function regularization is varied, the isoscalar central component exhibits a rather large cutoff variation. This reveals a surprisingly large numerical factor of the deltaful two-pion exchange potentials. The power counting is adjusted accordingly and we discuss the results and how to improve upon this finding.