Theory of Elastic Vector Meson Production

TL;DR

This paper reviews theoretical models of elastic vector meson production at HERA, comparing approaches based on wave functions and parton-hadron duality, with a focus on recent perturbative QCD developments and off-diagonal parton distributions.

Contribution

It provides a comparative analysis of different theoretical models, highlighting recent refinements and the importance of off-diagonal parton distributions in vector meson production.

Findings

Models with vector meson wave functions show varying success.

Parton-hadron duality approach offers an alternative perspective.

Refinements improve agreement with experimental data.

Abstract

The elastic production of vector mesons at HERA is discussed from the theoretical point of view. We briefly review different models, their successes and shortcomings. Main emphasis is put on recent issues in perturbative QCD calculations. Models including the vector meson wave function are compared with an approach based on parton-hadron duality. We discuss several refinements of these models in some detail, including the important role of off-diagonal parton distributions.