Vector meson-nucleon scattering length $|\alpha_{VN}|$ and trace anomalous energy contribution to the nucleon mass $T_{A}$

TL;DR

This paper explores the relationship between vector meson-nucleon scattering length and the trace anomaly contribution to the proton mass, providing a novel method to estimate the latter using scattering data.

Contribution

It establishes a link between scattering length measurements and the trace anomaly contribution to the proton mass, offering a new approach to study nucleon mass origin.

Findings

Estimated the trace anomaly contribution to proton mass as 22.8% ± 1.2%.

Found the trace anomaly contribution consistent with lattice QCD results.

Proposed that the trace anomaly contribution is independent of vector meson type.

Abstract

Low-energy scattering processes of vector meson and nucleon are an important window for studying non-perturbative QCD. The interaction of vector meson with nucleon, vector meson-nucleon scattering length $|\alpha_{VN}|$, is an important component of the study of hadronic interactions. Nowadays many scattering length values $|\alpha_{VN}|$ have been reported using the recent photoproduction experiment data or quasi data. In addition, the study of trace anomalous energy contribution to the proton mass is also a hot topic in non-perturbative QCD and hadron physics. However, it is difficult to measure proton trace anomalous energy experimentally, and the study of the trace anomaly of proton is still inconclusive. In this study, we established the relationship between the scattering length of the vector meson-proton $|\alpha_{Vp}|$ and the trace anomaly contribution of the proton mass $T_{A}$. With the scattering length values extracted by using the Vector Meson Dominance model, we obtained the trace anomaly contribution of the proton mass $T_{A}$ = (22.8$\%$ $\pm$ 1.2$\%$), which is of similar order of magnitude as the 23$\%$ given by Lattice QCD calculation. We conjecture that the trace anomaly contribution of nucleon is independent of the type of vector meson probe. We hope that high precision measurements of vector meson-nucleon scattering length could give us a better chance to explore the origin of the nucleon mass.