Threshold Upsilon-meson Photoproduction at EIC and EicC

TL;DR

This paper discusses how future high-precision photoproduction data from EIC and EicC can measure the $$-meson scattering length, providing insights into strong interactions and comparing it with other vector mesons.

Contribution

It introduces a method to extract the $ p$ scattering length from near-threshold photoproduction data using a Vector-Meson Dominance model and compares it with other mesons.

Findings

Projected data will enable precise measurement of $ p$ scattering length.

Comparison with $ p$, $ p$, and $J/ p$ scattering lengths reveals meson-specific effects.

The role of the 'young' vector-meson effect is evaluated.

Abstract

High-accuracy $\Upsilon$-meson photoproduction data from EIC and EicC experiments will allow the measurement of the near-threshold total cross section of the reaction $\gamma p\to\Upsilon p$, from which the absolute value of the $\Upsilon p$ scattering length, $|\alpha_{\Upsilon p}|$, can be extracted using a Vector-Meson Dominance model. For this evaluation, we used $\Upsilon$-meson photoproduction quasi-data from the QCD approach (the production amplitude can be factorized in terms of gluonic generalized parton distributions and the quarkonium distribution amplitude). A comparative analysis of $|\alpha_{\Upsilon p}|$ with the recently determined scattering lengths for $\omega p$, $\phi p$, and $J/\psi p$ using the A2, CLAS, and GlueX experimental data are performed. The role of the "young" vector-meson effect is evaluated.