Gravitational form factors of the nucleon in the Skyrme model based on scale-invariant chiral perturbation theory

Tanaka, Mitsuru*; Fujii, Daisuke; Kawaguchi, Mamiya*

We study the impact of the QCD scale anomaly on the gravitational form factors of the nucleon, focusing in particular on the form factor, the associated stress distribution, and internal force structure. Our analysis is based on a Skyrme model constructed within the framework of scale-invariant chiral perturbation theory. This model incorporates both the pion and a scalar meson, which represent the effects of the current quark mass and the gluonic quantum contributions to the scale anomaly, respectively. By varying the scalar meson mass, we investigate how the gluonic part of the scale anomaly affects the mechanical properties of the nucleon. We find that the gluonic contribution is essential for satisfying the stability conditions of the nucleon and generating the confining pressure. We also calculate the momentum-transfer dependence of , and the result shows good agreement with lattice QCD.