Speaker
Description
We present a systematic study of the gravitational (energy-momentum tensor) form factors of the nucleon and the baryon octet within the pion mean-field approach (chiral quark-soliton model), focusing on the role of the strange quark in the mechanical structure of baryons. Carrying out the flavor decomposition of the mass ($A$), angular-momentum ($J$), $D$-term, and $\bar{c}$ form factors, we find that strange-quark contributions are mild for the proton mass and spin---about $6\%$ of the momentum fraction and $4\%$ of the spin---yet become non-negligible for the $D$-term form factor ($D^{s}_{p} \approx -0.44$), so that the strange quark plays an essential role in the proton's pressure and shear-force distributions. We further analyze the flavor structure of the higher-twist $\bar{c}$ form factor and show how the quark-flavor contributions combine to preserve the von Laue stability condition. Extending the analysis to the full octet with flavor $\mathrm{SU(3)}$ symmetry breaking, we demonstrate that strangeness makes heavier hyperons both energetically and mechanically more compact, while the local stability conditions remain intact. These results clarify how the strange quark contributes to the mass, spin, and internal forces of baryons.