Speaker
Description
A dual identity of the $\sigma$ meson is proposed and its implications for the gravitational structure of hadrons is examined. Staring from a $q\bar{q}$ bound state view for the $\sigma$ meson, which emerges naturally as the chiral partner of the pion in the Dyson-Schwinger Equation formalism, with both states' properties tightly connected to the mechanisms of mass generation in QCD. We find that, above a critical coupling that triggers dynamical chiral symmetry breaking, the D-terms of the constituent quark, the pion, and $\sigma$ saturate at fixed values $D_{q,\pi,\sigma}=-1/3,-1,-7/3$. By examining the coupling strength evolution of the D-terms, this pattern follows naturally once a dual nature for the $\sigma$ meson is recognized: it behaves both as a quark–antiquark composite and as a dilaton arising from spontaneous scale symmetry breaking. This unified picture yields the prediction $D_N\sim -3$ for the nucleon D-term, consistent with lattice QCD, dispersive analyses, and diverse continuum studies.
| 请选择分会 | 强子物理与味物理 |
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