Extracting the Distribution Amplitudes of the rho meson from the Color Glass Condensate

TL;DR

This paper extracts the rho meson's distribution amplitudes from HERA diffractive data using CGC-inspired models, finding results consistent with theoretical predictions and highlighting model dependencies.

Contribution

It provides the first extraction of rho meson distribution amplitudes from experimental data using CGC and Regge dipole models, comparing with theoretical predictions.

Findings

Twist-2 DA is model-independent and aligns with QCD Sum Rules and lattice results.

Twist-3 DA is more model-dependent but still consistent with Sum Rules.

Extraction method offers a new way to study meson structure from experimental data.

Abstract

We extract the leading twist-2 and subleading twist-3 Distribution Amplitudes (DAs) of the rho meson using the HERA data on diffractive rho photoproduction. We do so using several Colour Glass Condensate (CGC) inspired and a Regge inspired dipole models. We find that our extracted twist-2 DA is not much model dependent and is consistent with QCD Sum Rules and lattice predictions. The extracted twist-3 DA is more model dependent but is still consistent with the Sum Rules prediction.