Implications of Large-$N_c$ QCD for the NN Interaction

TL;DR

This paper develops a method to classify two-nucleon interactions based on their scaling with the number of QCD colors, $N_c$, and explores its consistency with existing data and potential applications.

Contribution

It introduces a large-$N_c$ scaling approach for two-nucleon interactions and discusses its implications and limitations in nuclear physics.

Findings

Data supports the large-$N_c$ ordering in two-nucleon interactions.

The method may be applicable to weak and beyond-the-standard-model interactions.

Potential pitfalls can affect the reliability of the large-$N_c$ classification.

Abstract

We present a method for ordering two-nucleon interactions based upon their scaling with the number of QCD colors, $N_c$, in the limit that $N_c$ becomes large. Available data in the two-nucleon sector shows general agreement with this ordering, indicating that the method may be useful in other contexts where data is less readily available. However, several caveats and potential pitfalls can make the large-$N_c$ ordering fragile and/or vulnerable to misinterpretation. We discuss the application of the large-$N_c$ analysis to two- and three-nucleon interactions, including those originating from weak and beyond-the-standard-model interactions, as well as two-nucleon external currents. Finally, we discuss some open questions in the field.