Determination of the Gluonic D-term and Mechanical Radii of Proton from Experimental data

Abstract

We apply a "color" tripole ansatz for describing the $D$-term of the proton. By fitting the experimental data of the vector meson J/$\psi$ and $\phi$ photoproductions near the thresholds, we firstly obtained the gluonic $D$-term of the proton. $D_g(0)$ is estimated to be $-2.16\pm0.42$ for J/$\psi$ and $-1.31\pm0.48$ for $\phi$, and the mechanical root mean square radius of proton is estimated to be $0.61\pm0.29$ fm for $\phi$ and $0.42\pm0.11$ fm for J/$\psi$.