Gravitational form factors of the proton from near-threshold vector meson photoproduction

TL;DR

This paper analyzes the gravitational form factors of the proton by connecting experimental data from vector meson photoproduction and deep virtual Compton scattering, providing insights into the proton's internal mass and mechanical structure.

Contribution

It introduces a comprehensive method combining experimental data and analytical continuation to determine the proton's gravitational form factors and internal properties.

Findings

Quark and gluon GFFs are extracted and compared with lattice QCD.

A model-independent quark D-term distribution is obtained.

Results are consistent across different analytical methods.

Abstract

We embark on a systematical analysis of the quark and gluon gravitational form factors (GFFs) of the proton, by connecting energy-momentum tensor (EMT) and the near-threshold vector meson photoproduction (NTVMP). Concretely, the quark contributions of GFFs are determined by global fitting the cross section of the lightest vector meson $\rho^0$ photoproduction. Combined with the gluon GFFs achieved from heavy quarkonium $J/\psi$ photoproduction data, the complete GFFs are obtained and compared with the experimental results and Lattice QCD determinations. In addition, we use the Resonances Via Pad\'{e} (RVP) method based on the Schlessinger Point Method (SPM) to obtain a model-independent quark $D$-term distribution by direct analytical continuation of Deep Virtual Compton Scattering (DVCS) experimental data. If errors are considered, the results obtained by RVP are basically consistent with those obtained by NTVMP. Moreover, the comprehensive information on GFFs helps us to uncover the mass distribution and mechanical properties inside the proton. This work is not only an important basis for delving the proton enigmatic properties, unraveling the secrets of the proton internal nature but also have significance theoretical guiding for future JLab and EICs experimental measurements.