Nucleon tensor form factors at large $N_{c}$

TL;DR

This paper studies nucleon tensor form factors in the large-$N_{c}$ limit, revealing valence quark dominance in some quantities and sea quark effects in others, with results aligning well with lattice QCD data.

Contribution

It provides a detailed analysis of nucleon tensor form factors at large $N_{c}$, including their dependence on pion mean field size and pion mass, offering new theoretical insights and predictions.

Findings

Tensor charge and anomalous tensor magnetic moment are valence quark dominated.

Tensor quadrupole moment shows significant sea quark effects.

Results agree with lattice QCD data and predict unmeasured quantities.

Abstract

We investigate nucleon tensor form factors in the large-$N_{c}$ limit. In this picture, the nucleon emerges as a state of the $N_c$ valence quarks, which were bound by pion mean fields that were created by the presence of the valence quarks self-consistently. We find that the tensor charge ($g^{u-d}_{T}=0.99$) and the anomalous tensor magnetic moment ($\kappa^{u+d}_{T}=7.61$) are dominated by valence quarks, while the tensor quadrupole moment ($Q^{u-d}_{T}=-7.02$) shows significant sea quark effects. We examine how these quantities vary as the average size of the pion mean field is changed, showing interpolation between non-relativistic quark and Skyrme limits. We also observe that $g^{u-d}_{T}$ and $\kappa^{u+d}_{T}$ depend weakly on the pion mass. In contrast, $Q^{u-d}_{T}$ exhibits strong enhancement near the chiral limit. The numerical results are in good agreement with available lattice QCD data and provide predictions for unmeasured quantities.