Deeply-virtual and photoproduction of mesons at higher-order and higher-twist

TL;DR

This paper explores higher-order and higher-twist effects in meson production processes, highlighting their roles in improving theoretical stability and understanding pseudo-scalar meson production, supported by recent experimental comparisons.

Contribution

It provides a comprehensive evaluation of twist-3 contributions in meson photoproduction, emphasizing the importance of higher-twist effects for pseudo-scalar mesons and their experimental validation.

Findings

Higher-order contributions stabilize theoretical predictions.

Higher-twist effects are crucial for pseudo-scalar meson production.

Recent twist-3 evaluations align with experimental data.

Abstract

Both deeply-virtual and photoproduction of mesons offer promising access to generalized parton distributions and complementary description of different kinematical regions. The higher-order contributions offer stabilizing effect with respect to the dependence on renormalization scales, while higher-twist effects have been identified as especially important in the case of the production of pseudo-scalar mesons. This was confirmed by recent evaluation of the complete twist-3 contribution to $\pi$ and $\eta$/$\eta'$ photoproduction and its confrontation with experimental data.