Scalar form factors and nuclear interactions

TL;DR

This paper investigates the unexpectedly large scalar-isoscalar component in two-pion exchange nucleon-nucleon interactions, linking it to non-perturbative effects seen in the pion-nucleon scalar form factor, challenging standard chiral perturbation theory predictions.

Contribution

It identifies the non-perturbative origin of the large scalar-isoscalar term and connects it to the pion-nucleon scalar form factor, providing new insights into nuclear force modeling.

Findings

The scalar-isoscalar term is abnormally large.

Non-perturbative effects are significant in this context.

The anomaly challenges existing chiral perturbation theory predictions.

Abstract

The scalar-isoscalar term in the two-pion exchange $NN$ potential is abnormally large and does not respect the hierarchy of effects predicted by chiral perturbation theory. We argue that this anomaly is associated with non-perturbative effects, which are also present in the $\pi N$ scalar form factor.