Medium modification of the nucleon mechanical properties: Abel tomography case

TL;DR

This study explores how the mechanical properties and internal force distributions of the nucleon change in nuclear matter using an in-medium modified Skyrme model and Abel transformation techniques.

Contribution

It introduces a framework combining the in-medium modified Skyrme model with Abel transformation to analyze medium modifications of nucleon mechanical properties.

Findings

Nucleon swells in nuclear matter with broadened mass distribution.

Mean square radii of mass and angular momentum increase in medium.

Force fields inside the nucleon are redistributed in nuclear matter.

Abstract

We investigate how the gravitational form factors of the nucleon undergo changes in nuclear matter, emphasizing the Abel transformation from the three-dimensional (3D) Breit frame to the two-dimensional (2D) light-front frame. Since the gravitational form factors reveal the mechanical structure of the nucleon, we examine also the medium modifications of the energy-momentum, pressure, and shear-force distributions. We scrutinize the stabilities of the nucleon in nuclear matter. For this purpose, we employ the in-medium modified SU(2) Skyrme model to study these mechanical quantities of the nucleon, since it provides a simple but clear framework. In this in-medium modified SU(2) Skyrme model, the modification of pionic properties is performed by using low-energy pion-nucleus scattering data and the saturation properties of nuclear matter near the normal nuclear matter density, $\rho_0=0.5m_\pi^3$. The results reveal how the nucleon swells in nuclear matter as the mass distribution of the nucleon is broadened in medium. We also show that the mean square radii corresponding to the mass and angular momentum distributions increase in nuclear medium. This feature is kept both in 3D and 2D cases. We visualize how the strong force fields inside the nucleon in the 2D plane are distributed and illustrate how these forces undergo change in nuclear matter.